Organic semiconductors

ABSTRACT

The invention relates to novel compounds containing one or more 1,3-dithiolo[4,5-d]phthalimide (“DTPI”) units, to methods for their preparation preparation and educts or intermediates used therein, to mixtures and formulations containing them, to the use of the compounds, mixtures and formulations as organic semiconductors in organic electronic (OE) devices, especially in organic photovoltaic (OPV) devices and organic photodetectors (OPD), and to OE, OPV and OPD devices comprising these compounds, mixtures or formulations.

TECHNICAL FIELD

The invention relates to novel compounds containing one or more 1,3-dithiolo[4,5-d]phthalimide (“DTPI”) units, to methods for their preparation and educts or intermediates used therein, to mixtures and formulations containing them, to the use of the compounds, mixtures and formulations as organic semiconductors in organic electronic (OE) devices, especially in organic photovoltaic (OPV) devices and organic photodetectors (OPD), and to OE, OPV and OPD devices comprising these compounds, mixtures or formulations.

BACKGROUND

In recent years, there has been development of organic semiconducting (OSC) materials in order to produce more versatile, lower cost electronic devices. Such materials find application in a wide range of devices or apparatus, including organic thin film transistors (OTFTs), organic light emitting diodes (OLEDs), organic photodetectors (OPDs), organic photovoltaic (OPV) cells, sensors, memory elements and logic circuits to name just a few. The organic semiconducting materials are typically present in the electronic device in the form of a thin layer.

Organic semiconducting (OSC) materials are receiving ever-growing attention mostly due to their lucrative commercial prospects in organic electronics manufactured by cost effective solution processing technology at low temperature. It is generally believed that OSCs have a number of advantage over their inorganic counterparts, such as the potential of fabricating lightweight flexible backplanes, the opportunity to make large area displays using low-cost, high speed solution based fabrication techniques, and their optical and electronic properties being fine-tuneable via rational chemical structure modifications.

The main disadvantages of the OSC materials currently known in prior art are their relatively low device performance and their modest thermal, photo and electrical stability. Over the past two decades a wide range of new π-conjugated polymers have been made available, and have shown improved performance in OE devices like OTFTs such as high charge carrier mobility, reaching or even surpassing that of amorphous silicon. In the meantime, power conversion efficiencies of OPV cells fabricated using low bandgap π-conjugated polymers as active electron donor materials have exceeded 10%.

The performance of OTFTs is principally based upon the charge carrier mobility of the semiconducting material and the current on/off ratio. Thus, for use in OTFTs the OSC should have a low conductivity in the off state and a high charge-carrier mobility, enabling a high on/off ratio in the OTFT. In addition, the OSC, if n-type, should be stable to oxidation i.e. have a high ionisation potential, as oxidative doping leads to reduced device performance, for example increased off current and threshold voltage shift. Further requirements for the OSC are good processability, especially for large-scale production of thin-film layers and desired patterns, and high stability, thin-film uniformity and integrity of the OSC layer.

In OPV cells, π-conjugated polymers and organic small molecules have found use as OSC in the photoactive layer, as they allow devices to be manufactured by solution-processing techniques such as spin casting, dip coating or ink jet printing. Solution processing can be carried out cheaper and on a larger scale, compared to the evaporative techniques used to make inorganic thin film devices. In photoactive layers containing a blend of an n-type OSC and a p-type OSC, typically a π-conjugated polymer, forming a bulk-heterojunction (BHJ), the π-conjugated polymer serves as the main absorber of the solar energy. Therefore a low band gap is a basic requirement for the polymer to absorb the maximum of the solar spectrum. Thus, for use in OPV cells and OPDs, the OSC should have a low bandgap, which enables improved light harvesting by the photoactive layer and can lead to higher power conversion efficiency.

Polymerising π-π-donor-acceptor (D-A) monomers to synthesize D-A copolymers through transition metal catalysed polycondensation is a known strategy to achieve low bandgap semiconducting polymers for OPV and OPD applications. Conjugated D-A copolymers have also been found to demonstrate high charge carrier mobilities in OTFTs. It is generally accepted that the alternating D-A structure facilitates stronger intermolecular interactions, leading to smaller π-π-stacking distance and efficient intermolecular charge transfer due to static attractions between the donor and the acceptor monomer units.

To date, a large number of conjugated π-structures have been synthesized which can be used as monomers for preparing conjugated OSC polymers. However, electron donor units remain overwhelmingly dominant in the pool of monomers mainly due to the relative ease of synthetic accessibility of building blocks and precursors. In contrast, there is only a limited number of electron acceptor units or monomers available.

Therefore, it is desired to increase the pool of electron acceptors by adding electron deficient π-units to make further promising D-A copolymers available.

Thus, there is still a need for OSC compounds which are suitable for use in OE devices like OTFTs, OPDs and OPV cells, and which show one or more of the above-mentioned desired properties.

It was an aim of the present invention to provide OSC compounds for use in OE devices like OTFTs, OPDs and OPV devices, which are easy to synthesize, especially by methods suitable for mass production, which show especially good processibility, high stability, good solubility in organic solvents, high charge carrier mobility, and a low bandgap. Another aim of the invention was to extend the pool of OSC materials having electron acceptor property. Other aims of the present invention are immediately evident to the expert from the following detailed description.

The inventors of the present invention have found that one or more of the above aims can be achieved by providing compounds having a divalent unit derived from π-extended phthalimide, like the 1,3-dithiolo[4,5-d]phthalimide (“DTPI”) units as disclosed and claimed hereinafter.

X. Gao, et al., Adv. Mater., 2007, 19 (19), 3037 and F. Octón et al., Chem. Mater., 2011, 23 (3), 851) disclose dibenzotetrathiafulvalene (DBTTF) bisimides. F. Octón et al., J. Org. Chem., 2011, 76 (1), 154 discloses tetrathiafulvalene (TTF) dicarboxylic diesters with fluorinated alkyl chains. In the synthesis routes to these compounds as disclosed in the above-mentioned documents the following intermediate is used

wherein R is an alkyl or fluoroalkyl group. However, these documents do neither disclose nor suggest compounds or their uses as described and claimed hereinafter.

SUMMARY

The invention relates to a compound comprising one or more divalent units of formula I

wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings

-   -   X¹, X² O or S,     -   Y O, S or CU¹U²,     -   U¹, U² an electron withdrawing group, preferably selected from         CN, C(═O)R or C(═O)OR, or U¹ and U² together form a carbocyclic,         heterocyclic, aromatic or heteroaromatic ring having 4 to 15         ring atoms that is optionally substituted by one or more groups         L, preferably by one or more groups F, Cl, —CN, —C(═O)—R⁰,         —C(═O)—OR⁰, —O—C(═O)—R⁰, —O—C(═O)—OR⁰, —C(═O)—NHR⁰ or         —C(═O)—NR⁰R⁰⁰,     -   R¹ H or straight-chain, branched or cyclic alkyl with 1 to 30,         preferably 1 to 20, C atoms, in which one or more CH₂ groups are         optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —C(═O)—O—,         —O—C(═O)—, —NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CR⁰═CR⁰⁰—, —CY¹═CY²— or         —C≡C— in such a manner that O and/or S atoms are not linked         directly to one another, and in which one or more H atoms are         optionally replaced by F, Cl, Br, I or CN, and in which one or         more CH₂ or CH₃ groups are optionally replaced by a cationic or         anionic group, or aryl, heteroaryl, arylalkyl, heteroarylalkyl,         aryloxy or heteroaryloxy, wherein each of the aforementioned         cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic,         does optionally contain fused rings, and is unsubstituted or         substituted by one or more identical or different groups L,     -   R straight-chain, branched or cyclic alkyl with 1 to 30,         preferably 1 to 20, C atoms, in which one or more CH₂ groups are         optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —C(═O)—O—,         —O—C(═O)—, —NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CR⁰═CR⁰⁰—, —CY¹═CY²— or         —C≡C— in such a manner that O and/or S atoms are not linked         directly to one another, and in which one or more H atoms are         optionally replaced by F, Cl, Br, I or CN, and in which one or         more CH₂ or CH₃ groups are optionally replaced by a cationic or         anionic group, or aryl, heteroaryl, arylalkyl or         heteroarylalkyl, wherein each of the aforementioned cyclic         groups has 5 to 20 ring atoms, is mono- or polycyclic, does         optionally contain fused rings, and is unsubstituted or         substituted by one or more identical or different groups L,     -   L F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R⁰, OR⁰, SR⁰,         —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰,         —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃R⁰, —SO₂R⁰, —OH, —NO₂,         —CF₃, —SF₅, or optionally substituted silyl, or carbyl or         hydrocarbyl with 1 to 20 C atoms that is optionally substituted         and optionally comprises one or more hetero atoms, preferably F,         —CN, R⁰, —OR⁰, —SR⁰, —C(═O)—R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰,         —O—C(═O)—OR⁰, —C(═O)—NHR⁰, —C(═O)—NR⁰R⁰⁰,     -   Y¹, Y² H, F, Cl or CN,     -   X⁰ halogen, preferably F or Cl,     -   R⁰, R⁰⁰ H or straight-chain or branched alkyl with 1 to 20,         preferably 1 to 12, C atoms that is optionally fluorinated, and

with the proviso that, if X¹, X² and Y are O, the unit of formula I is bonded via the 1- or 4-position of the benzene ring to at least one group that is different from H (i.e. the unit of formula I is not bonded to two H atoms).

The invention further relates to a compound as described above and below which is a conjugated polymer. The conjugated polymer comprises, preferably consists of, one or more units of formula I and one or more arylene or heteroarylene units that have from 5 to 20 ring atoms, are mono- or polycyclic, do optionally contain fused rings, are unsubstituted or substituted by one or more identical or different groups L, and are either selected of formula I or are structurally different from formula I, and wherein all the aforementioned units are directly connected to each other.

The invention further relates to a compound as described above and below which is a small molecule or an oligomer.

The invention further relates to the use of the units of formula I in or as repeating units in conjugated polymers.

The invention further relates to the use of units of formula I in or as repeating units having electron acceptor property in conjugated polymers.

The invention further relates to a conjugated polymer comprising one or more electron acceptor repeating units comprising a unit of formula I, and preferably further comprising one or more repeating units having electron donor property.

The invention further relates to a monomer containing a unit of formula I, and optionally containing one or more additional arylene or heteroarylene units, and further containing one or more reactive groups which can be reacted to form a conjugated polymer as described above and below.

The invention further relates to the use of a compound as described above and below as electron acceptor or n-type semiconductor.

The invention further relates to the use of a conjugated polymer as described above and below as semiconductor, preferably as electron donor or p-type semiconductor.

The invention further relates to the use of a compound as described above and below as electron donor or electron acceptor component in a semiconducting material, formulation, polymer blend, device or component of a device.

The invention further relates to a semiconducting material, formulation, polymer blend, device or component of a device comprising a compound as described above and below as electron donor component, and preferably further comprising one or more compounds having electron acceptor properties.

The invention further relates to a mixture, which may also be a polymer blend, comprising one or more compounds as described above and below, and further comprising one or more additional compounds selected from compounds having one or more of semiconducting, charge transport, hole or electron transport, hole or electron blocking, electrically conducting, photoconducting or light emitting properties.

The invention further relates to a mixture comprising one or more compounds as described above and below, and further comprising one or more n-type organic semiconductors, preferably selected from fullerenes or substituted fullerenes.

The invention further relates to a formulation comprising one or more compounds or mixtures as described above and below, and further comprising one or more solvents, preferably selected from organic solvents.

The invention further relates to an organic semiconducting formulation comprising one or more compounds as described above and below, and further comprising one or more organic binders or precursors thereof, preferably having a permittivity c at 1,000 Hz and 20° C. of 3.3 or less, and optionally one or more solvents preferably selected from organic solvents.

The invention further relates to an optical, electrooptical, electronic, electroluminescent or photoluminescent device, or a component thereof, or an assembly comprising it, which is prepared using a formulation according to the present invention.

The invention further relates to the use of a compound or mixture as described above and below as semiconducting, charge transport, electrically conducting, photoconducting or light emitting material, or in an optical, electrooptical, electronic, electroluminescent or photoluminescent device, or in a component of such a device or in an assembly comprising such a device or component

The invention further relates to a semiconducting, charge transport, electrically conducting, photoconducting or light emitting material comprising a compound or mixture as described above and below.

The invention further relates to an optical, electrooptical, electronic, electroluminescent or photoluminescent device, or a component thereof, or an assembly comprising it, which comprises a compound or mixture as described above and below, or comprises a semiconducting, charge transport, electrically conducting, photoconducting or light emitting material as described above and below.

The optical, electrooptical, electronic, electroluminescent and photoluminescent device includes, without limitation, organic thin film transistors (OTFT), organic thin film transistors (OTFT), organic light emitting diodes (OLED), organic light emitting transistors (OLET), organic photovoltaic devices (OPV), organic photodetectors (OPD), organic solar cells, dye-sensitized solar cells (DSSC), perovskite-based solar cells, laser diodes, Schottky diodes, photoconductors and photodetectors.

Preferred devices are OTFTs, OTFTs, OPVs, OPDs and OLEDs, in particular bulk heterojunction (BHJ) OPVs or inverted BHJ OPVs.

Further preferred is the use of a compound or mixture as described above and below as dye in a DSSC or a perovskite-based solar cell. Further preferred is a DSSC or perovskite-based solar cells comprising a compound or mixture as described above and below.

The component of the above devices includes, without limitation, charge injection layers, charge transport layers, interlayers, planarising layers, antistatic films, polymer electrolyte membranes (PEM), conducting substrates and conducting patterns.

The assembly comprising such a device or component includes, without limitation, integrated circuits (IC), radio frequency identification (RFID) tags or security markings or security devices containing them, flat panel displays or backlights thereof, electrophotographic devices, electrophotographic recording devices, organic memory devices, sensor devices, biosensors and biochips.

In addition the compounds, mixtures and formulations of the present invention can be used as electrode materials in batteries and in components or devices for detecting and discriminating DNA sequences.

The invention further relates to a bulk heterojunction which comprises, or is being formed from, a mixture comprising one or more compounds according to the present invention and one or more n-type organic semiconductors that are preferably selected from fullerenes or substituted fullerenes. The invention further relates to a bulk heterojunction (BHJ) OPV device or inverted BHJ OPV device, comprising such a bulk heterojunction.

Terms and Definitions

As used herein, the term “polymer” will be understood to mean a molecule of high relative molecular mass, the structure of which essentially comprises multiple repetitions of units derived, actually or conceptually, from molecules of low relative molecular mass (Pure Appl. Chem., 1996, 68, 2291). The term “oligomer” will be understood to mean a molecule of intermediate relative molecular mass, the structure of which essentially comprises a small plurality of units derived, actually or conceptually, from molecules of lower relative molecular mass (Pure Appl. Chem., 1996, 68, 2291). In a preferred meaning as used herein present invention a polymer will be understood to mean a compound having >1, i.e. at least 2 repeat units, preferably ≥5 repeat units, and an oligomer will be understood to mean a compound with >1 and <10, preferably <5, repeat units.

Further, as used herein, the term “polymer” will be understood to mean a molecule that encompasses a backbone (also referred to as “main chain”) of one or more distinct types of repeat units (the smallest constitutional unit of the molecule) and is inclusive of the commonly known terms “oligomer”, “copolymer”, “homopolymer”, “random polymer” and the like. Further, it will be understood that the term polymer is inclusive of, in addition to the polymer itself, residues from initiators, catalysts and other elements attendant to the synthesis of such a polymer, where such residues are understood as not being covalently incorporated thereto. Further, such residues and other elements, while normally removed during post polymerization purification processes, are typically mixed or co-mingled with the polymer such that they generally remain with the polymer when it is transferred between vessels or between solvents or dispersion media.

As used herein, in a formula showing a polymer or a repeat unit, like for example a unit of formula I or a polymer of formula III or IV or their subformulae, an asterisk (*) will be understood to mean a chemical linkage to an adjacent unit or to a terminal group in the polymer backbone. In a ring, like for example a benzene or thiophene ring, an asterisk (*) will be understood to mean a C atom that is fused to an adjacent ring.

As used herein, the terms “repeat unit”, “repeating unit” and “monomeric unit” are used interchangeably and will be understood to mean the constitutional repeating unit (CRU), which is the smallest constitutional unit the repetition of which constitutes a regular macromolecule, a regular oligomer molecule, a regular block or a regular chain (Pure Appl. Chem., 1996, 68, 2291). As further used herein, the term “unit” will be understood to mean a structural unit which can be a repeating unit on its own, or can together with other units form a constitutional repeating unit.

As used herein, a “terminal group” will be understood to mean a group that terminates a polymer backbone. The expression “in terminal position in the backbone” will be understood to mean a divalent unit or repeat unit that is linked at one side to such a terminal group and at the other side to another repeat unit. Such terminal groups include endcap groups, or reactive groups that are attached to a monomer forming the polymer backbone which did not participate in the polymerisation reaction, like for example a group having the meaning of R⁵ or R⁶ as defined below.

As used herein, the term “endcap group” will be understood to mean a group that is attached to, or replacing, a terminal group of the polymer backbone. The endcap group can be introduced into the polymer by an endcapping process. Endcapping can be carried out for example by reacting the terminal groups of the polymer backbone with a monofunctional compound (“endcapper”) like for example an alkyl- or arylhalide, an alkyl- or arylstannane or an alkyl- or arylboronate. The endcapper can be added for example after the polymerisation reaction. Alternatively the endcapper can be added in situ to the reaction mixture before or during the polymerisation reaction. In situ addition of an endcapper can also be used to terminate the polymerisation reaction and thus control the molecular weight of the forming polymer. Typical endcap groups are for example H, phenyl and lower alkyl.

As used herein, the term “small molecule” will be understood to mean a monomeric compound which typically does not contain a reactive group by which it can be reacted to form a polymer, and which is designated to be used in monomeric form. In contrast thereto, the term “monomer” unless stated otherwise will be understood to mean a monomeric compound that carries one or more reactive functional groups by which it can be reacted to form a polymer.

As used herein, the terms “donor” or “donating” and “acceptor” or “accepting” will be understood to mean an electron donor or electron acceptor, respectively. “Electron donor” will be understood to mean a chemical entity that donates electrons to another compound or another group of atoms of a compound. “Electron acceptor” will be understood to mean a chemical entity that accepts electrons transferred to it from another compound or another group of atoms of a compound. See also International Union of Pure and Applied Chemistry, Compendium of Chemical Technology, Gold Book, Version 2.3.2, 19. August 2012, pages 477 and 480.

As used herein, the term “n-type” or “n-type semiconductor” will be understood to mean an extrinsic semiconductor in which the conduction electron density is in excess of the mobile hole density, and the term “p-type” or “p-type semiconductor” will be understood to mean an extrinsic semiconductor in which mobile hole density is in excess of the conduction electron density (see also, J. Thewlis, Concise Dictionary of Physics, Pergamon Press, Oxford, 1973).

As used herein, the term “leaving group” will be understood to mean an atom or group (which may be charged or uncharged) that becomes detached from an atom in what is considered to be the residual or main part of the molecule taking part in a specified reaction (see also Pure Appl. Chem., 1994, 66, 1134).

As used herein, the term “conjugated” will be understood to mean a compound (for example a polymer) that contains mainly C atoms with sp²-hybridisation (or optionally also sp-hybridisation), and wherein these C atoms may also be replaced by hetero atoms. In the simplest case this is for example a compound with alternating C—C single and double (or triple) bonds, but is also inclusive of compounds with aromatic units like for example 1,4-phenylene. The term “mainly” in this connection will be understood to mean that a compound with naturally (spontaneously) occurring defects, or with defects included by design, which may lead to interruption of the conjugation, is still regarded as a conjugated compound.

As used herein, unless stated otherwise the molecular weight is given as the number average molecular weight M_(n) or weight average molecular weight M_(w), which is determined by gel permeation chromatography (GPC) against polystyrene standards in eluent solvents such as tetrahydrofuran, trichloromethane (TCM, chloroform), chlorobenzene or 1,2,4-trichlorobenzene. Unless stated otherwise, chlorobenzene is used as solvent. The degree of polymerization, also referred to as total number of repeat units, n, will be understood to mean the number average degree of polymerization given as n=M_(n)/M_(U), wherein M_(n) is the number average molecular weight and M_(U) is the molecular weight of the single repeat unit, see J. M. G. Cowie, Polymers: Chemistry & Physics of Modern Materials, Blackie, Glasgow, 1991.

As used herein, the term “carbyl group” will be understood to mean any monovalent or multivalent organic moiety which comprises at least one carbon atom either without any non-carbon atoms (like for example —C≡C—), or optionally combined with at least one non-carbon atom such as B, N, O, S, P, Si, Se, As, Te or Ge (for example carbonyl etc.).

As used herein, the term “hydrocarbyl group” will be understood to mean a carbyl group that does additionally contain one or more H atoms and optionally contains one or more hetero atoms like for example B, N, O, S, P, Si, Se, As, Te or Ge.

As used herein, the term “hetero atom” will be understood to mean an atom in an organic compound that is not an H- or C-atom, and preferably will be understood to mean B, N, O, S, P, Si, Se, As, Te or Ge.

A carbyl or hydrocarbyl group comprising a chain of 3 or more C atoms may be straight-chain, branched and/or cyclic, and may include spiro-connected and/or fused rings.

Preferred carbyl and hydrocarbyl groups include alkyl, alkoxy, thioalkyl, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy and alkoxycarbonyloxy, each of which is optionally substituted and has 1 to 40, preferably 1 to 25, very preferably 1 to 18 C atoms, furthermore optionally substituted aryl or aryloxy having 6 to 40, preferably 6 to 25 C atoms, furthermore alkylaryloxy, arylcarbonyl, aryloxycarbonyl, arylcarbonyloxy and aryloxycarbonyloxy, each of which is optionally substituted and has 6 to 40, preferably 7 to 40 C atoms, wherein all these groups do optionally contain one or more hetero atoms, preferably selected from B, N, O, S, P, Si, Se, As, Te and Ge.

Further preferred carbyl and hydrocarbyl group include for example: a C₁-C₄₀ alkyl group, a C₁-C₄₀ fluoroalkyl group, a C₁-C₄₀ alkoxy or oxaalkyl group, a C₂-C₄₀ alkenyl group, a C₂-C₄₀ alkynyl group, a C₃-C₄₀ allyl group, a C₄-C₄₀ alkyldienyl group, a C₄-C₄₀ polyenyl group, a C₂-C₄₀ ketone group, a C₂-C₄₀ ester group, a C₆-C₁₈ aryl group, a C₆-C₄₀ alkylaryl group, a C₆-C₄₀ arylalkyl group, a C₄-C₄₀ cycloalkyl group, a C₄-C₄₀ cycloalkenyl group, and the like. Preferred among the foregoing groups are a C₁-C₂₀ alkyl group, a C₁-C₂₀ fluoroalkyl group, a C₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₃-C₂₀ allyl group, a C₄-C₂₀ alkyldienyl group, a C₂-C₂₀ ketone group, a C₂-C₂₀ ester group, a C₆-C₁₂ aryl group, and a C₄-C₂₀ polyenyl group, respectively.

Also included are combinations of groups having carbon atoms and groups having hetero atoms, like e.g. an alkynyl group, preferably ethynyl, that is substituted with a silyl group, preferably a trialkylsilyl group.

The carbyl or hydrocarbyl group may be an acyclic group or a cyclic group. Where the carbyl or hydrocarbyl group is an acyclic group, it may be straight-chain or branched. Where the carbyl or hydrocarbyl group is a cyclic group, it may be a non-aromatic carbocyclic or heterocyclic group, or an aryl or heteroaryl group.

A non-aromatic carbocyclic group as referred to above and below is saturated or unsaturated and preferably has 4 to 30 ring C atoms. A non-aromatic heterocyclic group as referred to above and below preferably has 4 to 30 ring C atoms, wherein one or more of the C ring atoms are optionally replaced by a hetero atom, preferably selected from N, O, S, Si and Se, or by a —S(O)— or —S(O)₂— group. The non-aromatic carbo- and heterocyclic groups are mono- or polycyclic, may also contain fused rings, preferably contain 1, 2, 3 or 4 fused or unfused rings, and are optionally substituted with one or more groups L, wherein

L is selected from F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, —R⁰, —OR⁰, —SR⁰, —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰, —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃R⁰, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, wherein X⁰ is halogen, preferably F or Cl, and R⁰, R⁰⁰ denote H or straight-chain or branched alkyl with 1 to 20, preferably 1 to 12 C atoms that is optionally fluorinated.

Preferably L is selected from F, —CN, R⁰, —OR⁰, —SR⁰, —C(═O)—R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —O—C(═O)—OR⁰, —C(═O)—NHR⁰ and —C(═O)—NR⁰R⁰⁰.

Further preferably L is selected from F or alkyl, alkoxy, oxaalkyl, thioalkyl, fluoroalkyl, fluoroalkoxy, alkylcarbonyl, alkoxycarbonyl, with 1 to 12 C atoms, or alkenyl or alkynyl with 2 to 12 C atoms.

Preferred non-aromatic carbocyclic or heterocyclic groups are tetrahydrofuran, indane, pyran, pyrrolidine, piperidine, cyclopentane, cyclohexane, cycloheptane, cyclopentanone, cyclohexanone, dihydro-furan-2-one, tetrahydro-pyran-2-one and oxepan-2-one.

An aryl group as referred to above and below preferably has 4 to 30 ring C atoms, is mono- or polycyclic and may also contain fused rings, preferably contains 1, 2, 3 or 4 fused or unfused rings, and is optionally substituted with one or more groups L as defined above.

A heteroaryl group as referred to above and below preferably has 4 to 30 ring C atoms, wherein one or more of the C ring atoms are replaced by a hetero atom, preferably selected from N, O, S, Si and Se, is mono- or polycyclic and may also contain fused rings, preferably contains 1, 2, 3 or 4 fused or unfused rings, and is optionally substituted with one or more groups L as defined above.

An arylalkyl or heteroarylalkyl group as referred to above and below preferably denotes —(CH₂)_(a)-aryl or —(CH₂)_(a)-heteroaryl, wherein a is an integer from 1 to 6, preferably 1, and “aryl” and “heteroaryl” have the meanings given above and below. A preferred arylalkyl group is benzyl which is optionally substituted by L.

As used herein, “arylene” will be understood to mean a divalent aryl group, and “heteroarylene” will be understood to mean a divalent heteroaryl group, including all preferred meanings of aryl and heteroaryl as given above and below.

Preferred aryl and heteroaryl groups are phenyl in which, in addition, one or more CH groups may be replaced by N, naphthalene, thiophene, selenophene, thienothiophene, dithienothiophene, fluorene and oxazole, all of which can be unsubstituted, mono- or polysubstituted with L as defined above. Very preferred aryl and heteroaryl groups are selected from pyrrole, preferably N-pyrrole, furan, pyridine, preferably 2- or 3-pyridine, pyrimidine, pyridazine, pyrazine, triazole, tetrazole, pyrazole, imidazole, isothiazole, thiazole, thiadiazole, isoxazole, oxazole, oxadiazole, thiophene, preferably 2-thiophene, selenophene, preferably 2-selenophene, 2,5-dithiophene-2′,5′-diyl, thieno[3,2-b]thiophene, thieno[2,3-b]thiophene, furo[3,2-b]furan, furo[2,3-b]furan, seleno[3,2-b]selenophene, seleno[2,3-b]selenophene, thieno[3,2-b]selenophene, thieno[3,2-b]furan, indole, isoindole, benzo[b]furan, benzo[b]thiophene, benzo[1,2-b;4,5-b′]dithiophene, benzo[2,1-b;3,4-b′]dithiophene, quinole, 2-methylquinole, isoquinole, quinoxaline, quinazoline, benzotriazole, benzimidazole, benzothiazole, benzisothiazole, benzisoxazole, benzoxadiazole, benzoxazole, benzothiadiazole, 4H-cyclopenta[2,1-b;3,4-b′]dithiophene, 7H-3,4-dithia-7-sila-cyclopenta[a]pentalene, all of which can be unsubstituted, mono- or polysubstituted with L as defined above. Further examples of aryl and heteroaryl groups are those selected from the groups shown hereinafter.

An alkyl group or an alkoxy group, i.e., where the terminal CH₂ group is replaced by —O—, can be straight-chain or branched. It is preferably straight-chain, has 2, 3, 4, 5, 6, 7, 8, 12 or 16 carbon atoms and accordingly is preferably ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, dodecyl or hexadecyl, ethoxy, propoxy, butoxy, pentoxy, hexoxy, heptoxy, octoxy, dodecoxy or hexadecoxy, furthermore methyl, nonyl, decyl, undecyl, tridecyl, tetradecyl, pentadecyl, nonoxy, decoxy, undecoxy, tridecoxy or tetradecoxy, for example.

An alkenyl group, i.e., wherein one or more CH₂ groups are replaced by —CH═CH— can be straight-chain or branched. It is preferably straight-chain, has 2 to 10 C atoms and accordingly is preferably vinyl, prop-1-, or prop-2-enyl, but-1-, 2- or but-3-enyl, pent-1-, 2-, 3- or pent-4-enyl, hex-1-, 2-, 3-, 4- or hex-5-enyl, hept-1-, 2-, 3-, 4-, 5- or hept-6-enyl, oct-1-, 2-, 3-, 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, dec-1-, 2-, 3-, 4-, 5-, 6-, 7-, 8- or dec-9-enyl.

Especially preferred alkenyl groups are C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl, C₅-C₇-4-alkenyl, C₆-C₇-5-alkenyl and C₇-6-alkenyl, in particular C₂-C₇-1E-alkenyl, C₄-C₇-3E-alkenyl and C₅-C₇-4-alkenyl. Examples for particularly preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups having up to 5 C atoms are generally preferred.

An oxaalkyl group, i.e., where one CH₂ group is replaced by —O—, is preferably straight-chain 2-oxapropyl (=methoxymethyl), 2-(=ethoxymethyl) or 3-oxabutyl (=2-methoxyethyl), 2-, 3-, or 4-oxapentyl, 2-, 3-, 4-, or 5-oxahexyl, 2-, 3-, 4-, 5-, or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8-oxanonyl or 2-, 3-, 4-, 5-, 6-,7-, 8- or 9-oxadecyl, for example.

In an alkyl group wherein one CH₂ group is replaced by —O— and one CH₂ group is replaced by —C(O)—, these radicals are preferably neighboured. Accordingly these radicals together form a carbonyloxy group —C(O)—O— or an oxycarbonyl group —O—C(O)—. Preferably this group is straight-chain and has 2 to 6 C atoms. It is accordingly preferably acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyloxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2-(methoxycarbonyl)ethyl, 2-(ethoxycarbonyl)ethyl, 2-(propoxycarbonyl)ethyl, 3-(methoxycarbonyl)propyl, 3-(ethoxycarbonyl)propyl, 4-(methoxycarbonyl)-butyl.

An alkyl group wherein two or more CH₂ groups are replaced by —O— and/or —C(O)O— can be straight-chain or branched. It is preferably straight-chain and has 3 to 12 C atoms. Accordingly, it is preferably bis-carboxy-methyl, 2,2-bis-carboxy-ethyl, 3,3-bis-carboxy-propyl, 4,4-bis-carboxy-butyl, 5,5-bis-carboxy-pentyl, 6,6-bis-carboxy-hexyl, 7,7-bis-carboxy-heptyl, 8,8-bis-carboxy-octyl, 9,9-bis-carboxy-nonyl, 10,10-bis-carboxy-decyl, bis-(methoxycarbonyl)-methyl, 2,2-bis-(methoxycarbonyl)-ethyl, 3,3-bis-(methoxycarbonyl)-propyl, 4,4-bis-(methoxycarbonyl)-butyl, 5,5-bis-(methoxycarbonyl)-pentyl, 6,6-bis-(methoxycarbonyl)-hexyl, 7,7-bis-(methoxycarbonyl)-heptyl, 8,8-bis-(methoxycarbonyl)-octyl, bis-(ethoxycarbonyl)-methyl, 2,2-bis-(ethoxycarbonyl)-ethyl, 3,3-bis-(ethoxycarbonyl)-propyl, 4,4-bis-(ethoxycarbonyl)-butyl, 5,5-bis-(ethoxycarbonyl)-hexyl.

A thioalkyl group, i.e., where one CH₂ group is replaced by —S—, is preferably straight-chain thiomethyl (—SCH₃), 1-thioethyl (—SCH₂CH₃), 1-thiopropyl (═—SCH₂CH₂CH₃), 1-(thiobutyl), 1-(thiopentyl), 1-(thiohexyl), 1-(thioheptyl), 1-(thiooctyl), 1-(thiononyl), 1-(thiodecyl), 1-(thioundecyl) or 1-(thiododecyl), wherein preferably the CH₂ group adjacent to the sp² hybridised vinyl carbon atom is replaced.

A fluoroalkyl group is perfluoroalkyl C_(i)F_(2i+1), wherein i is an integer from 1 to 15, in particular CF₃, C₂F₅, C₃F₇, C₄F₉, C₅F₁₁, C₆F₁₃, C₇F₁₅ or C₈F₁₇, very preferably C₆F₁₃, or partially fluorinated alkyl, preferably with 1 to 15 C atoms, in particular 1,1-difluoroalkyl, all of the aforementioned being straight-chain or branched.

Preferably “fluoroalkyl” means a partially fluorinated (i.e. not perfluorinated) alkyl group.

Alkyl, alkoxy, alkenyl, oxaalkyl, thioalkyl, carbonyl and carbonyloxy groups can be achiral or chiral groups. Particularly preferred chiral groups are 2-butyl (=1-methylpropyl), 2-methylbutyl, 2-methylpentyl, 3-methylpentyl, 2-ethylhexyl, 2-butyloctyl, 2-hexyldecyl, 2-octyldodecyl, 2-propylpentyl, in particular 2-methylbutyl, 2-methylbutoxy, 2-methylpentoxy, 3-methylpentoxy, 2-ethyl-hexoxy, 2-butyloctoxyo, 2-hexyldecoxy, 2-octyldodecoxy, 1-methylhexoxy, 2-octyloxy, 2-oxa-3-methylbutyl, 3-oxa-4-methylpentyl, 4-methylhexyl, 2-hexyl, 2-octyl, 2-nonyl, 2-decyl, 2-dodecyl, 6-methoxy-octoxy, 6-methyloctoxy, 6-methyloctanoyloxy, 5-methylheptyloxy-carbonyl, 2-methylbutyryloxy, 3-methylvaleroyloxy, 4-methylhexanoyloxy, 2-chloro-propionyloxy, 2-chloro-3-methylbutyryloxy, 2-chloro-4-methyl-valeryl-oxy, 2-chloro-3-methylvaleryloxy, 2-methyl-3-oxapentyl, 2-methyl-3-oxahexyl, 1-methoxypropyl-2-oxy, 1-ethoxypropyl-2-oxy, 1-propoxypropyl-2-oxy, 1-butoxypropyl-2-oxy, 2-fluorooctyloxy, 2-fluorodecyloxy, 1,1,1-trifluoro-2-octyloxy, 1,1,1-trifluoro-2-octyl, 2-fluoromethyloctyloxy for example. Very preferred are 2-ethylhexyl, 2-butyloctyl, 2-hexyldecyl, 2-octyldodecyl, 2-hexyl, 2-octyl, 2-octyloxy, 1,1,1-trifluoro-2-hexyl, 1,1,1-trifluoro-2-octyl and 1,1,1-trifluoro-2-octyloxy.

Preferred achiral branched groups are isopropyl, isobutyl (=methylpropyl), isopentyl (=3-methylbutyl), tert. butyl, isopropoxy, 2-methyl-propoxy and 3-methylbutoxy.

In a preferred embodiment, the alkyl groups are independently of each other selected from primary, secondary or tertiary alkyl or alkoxy with 1 to 30 C atoms, wherein one or more H atoms are optionally replaced by F, or aryl, aryloxy, heteroaryl or heteroaryloxy that is optionally alkylated or alkoxylated and has 4 to 30 ring atoms. Very preferred groups of this type are selected from the group consisting of the following formulae

wherein “ALK” denotes optionally fluorinated, preferably linear, alkyl or alkoxy with 1 to 20, preferably 1 to 12 C-atoms, in case of tertiary groups very preferably 1 to 9 C atoms, and the dashed line denotes the link to the ring to which these groups are attached. Especially preferred among these groups are those wherein all ALK subgroups are identical.

As used herein, if an aryl(oxy) or heteroaryl(oxy) group is “alkylated or alkoxylated”, this means that it is substituted with one or more alkyl or alkoxy groups having from 1 to 20 C-atoms and being straight-chain or branched and wherein one or more H atoms are optionally substituted by an F atom.

Above and below, Y¹ and Y² are independently of each other H, F, Cl or CN. As used herein, —CO—, —C(═O)— and —C(O)— will be understood to mean a carbonyl group, i.e. a group having the structure

As used herein, C═CR¹R² will be understood to mean a group having the structure

As used herein, “halogen” includes F, Cl, Br or I, preferably F, Cl or Br. A halogen atom that represents a substituent on a ring or chain is preferably F or Cl, very preferably F. A halogen atom that represents a reactive group in a monomer is preferably Br or I.

DETAILED DESCRIPTION

The compounds of the present invention comprise the structural feature of a phthalimide moiety fused with a 1,3-dithiol ring (DTPI) bearing electron withdrawing substituents at the 2-position.

The compounds of the present invention are easy to synthesize and exhibit advantageous properties. They show good processability for the device manufacture process, high solubility in organic solvents, and are especially suitable for large scale production using solution processing methods.

Co-polymers derived from monomers of the present invention and electron donor monomers show low bandgaps, high charge carrier mobilities, high external quantum efficiencies in BHJ solar cells, good morphology when used in p/n-type blends e.g. with fullerenes, high oxidative stability, a long lifetime in electronic devices, and are promising materials for organic electronic OE devices, especially for OTFTs and OPV devices with high power conversion efficiency.

The compounds of the present invention are also suitable as p-type semiconductors for the preparation of blends of p-type and n-type semiconductors which are suitable for use in BHJ photovoltaic devices.

Besides, the compounds of the present invention show the following advantageous properties:

-   -   i) Additional solubility can be introduced into the compound by         inclusion of solubilising groups R¹, U¹ and/or U². Especially a         solubilising alkyl chain R¹ on the imide N-atom facilitate         synthesis and purification of the unit, and in addition         facilitates fine-tuning the solution processibility of the         resultant polymer.     -   ii) The S-atoms in the 1,3-dithiol ring enable stronger         interchain interactions, compared for example to         benzothiadiazole units.     -   iii) Additional fine-tuning of the electronic energies         (HOMO/LUMO levels) by co-polymerisation with appropriate         co-monomer(s) can afford attractive candidate materials for OPV         applications.     -   iv) The DTPI units have planar structures that enable strong         pi-pi stacking in the solid state leading to improved charge         transport properties in the form of higher charge carrier         mobility.     -   v) Using the DTPI unit together with electron donating units, it         is possible to create a donor-acceptor polymer, optionally with         spacer units like thiophene, bithiophene or thienothiophene to         keep the backbone flat. Such polymers are expected to have a         high Voc.

Very preferably R¹ and R in the units of formula I denote alkyl, alkoxy or thiaalkyl, all of which are straight-chain or branched, have 1 to 25, preferably 1 to 18 C atoms, and are optionally fluorinated.

If R¹ or R denote an aryl(oxy) or heteroaryl(oxy) group, it is preferably selected from phenyl, pyrrole, furan, pyridine, thiazole, thiophene, thieno[3,2-b]thiophene or thieno[2,3-b]thiophene, each of which is unsubstituted or substituted with F or alkyl, alkoxy or thioalkyl each having from 1 to 20 C atoms and being optionally fluorinated.

In another preferred embodiment of the present invention, R¹ and/or R denote straight-chain, branched or cyclic alkyl with 1 to 20 C-atoms wherein one or more CH₂ or CH₃ groups are substituted by a cationic or anionic group.

The cationic group is preferably selected from the group consisting of phosphonium, sulfonium, ammonium, uronium, thiouronium, guanidinium or heterocyclic cations such as imidazolium, pyridinium, pyrrolidinium, triazolium, morpholinium or piperidinium cation.

Preferred cationic groups are selected from the group consisting of tetraalkylammonium, tetraalkylphosphonium, N-alkylpyridinium, N,N-dialkylpyrrolidinium, 1,3-dialkylimidazolium, wherein “alkyl” preferably denotes a straight-chain or branched alkyl group with 1 to 12 C atoms.

Further preferred cationic groups are selected from the group consisting of the following formulae

wherein R¹′, R²′, R³′ and R⁴′ denote, independently of each other, H, a straight-chain or branched alkyl group with 1 to 12 C atoms or non-aromatic carbo- or heterocyclic group or an aryl or heteroaryl group, each of the aforementioned groups having 3 to 20, preferably 5 to 15, ring atoms, being mono- or polycyclic, and optionally being substituted by one or more identical or different substituents L as defined below, or denote a link to the respective group R¹⁻⁴.

In the above cationic groups of the above-mentioned formulae any one of the groups R¹′, R²′, R³′ and R⁴′ (if they replace a CH₃ group) can denote a link to the group R¹, or two neighbored groups R¹′, R²′, R³′ or R⁴′ (if they replace a CH₂ group) can denote a link to the respective group R¹⁻⁴.

The anionic group is preferably selected from the group consisting of borate, imide, phosphate, sulfonate, sulfate, succinate, naphthenate or carboxylate, very preferably from phosphate, sulfonate or carboxylate.

The compounds according to the present invention include small molecules, monomers, oligomers and polymers.

A preferred embodiment of the present invention relates to a conjugated polymer comprising, preferably consisting of, one or more units selected of formula I as defined above and below, and further comprising one or more arylene or heteroarylene units that have from 5 to 20 ring atoms, are mono- or polycyclic, do optionally contain fused rings, are unsubstituted or substituted by one or more identical or different groups L, and are either selected of formula I or are structurally different from formula I, and wherein all the aforementioned units are directly connected to each other.

Another preferred embodiment of the present invention relates to a conjugated polymer comprising, preferably consisting of, one or more repeating units of formula II1 or II2, and optionally one or more repeating units of formula II3: —(Ar¹)_(a)—U—(Ar²)_(b)—(Ar³)_(c)—(Ar⁴)_(d)—  II1 —(Ar¹)_(a)—(Ar²)_(b)—U—(Ar³)_(c)—(Ar⁴)_(d)—  II2 —(Ar¹)_(a)—(Ar²)_(b)—(Ar³)_(c)—(Ar⁴)_(d)—  II3

wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings

-   -   U a unit of formula I as defined above and below,     -   Ar¹⁻⁴ arylene or heteroarylene that has 5 to 20 ring atoms, is         mono- or polycyclic, does optionally contain fused rings, is         unsubstituted or substituted by one or more identical or         different groups L, and is different from formula I,     -   a, b, c, d 0 or 1, wherein in formula II3 a+b+c+d≥1.

Preferred units of formula II1 and II2 are those wherein a+b+c+d≥1.

Preferably the conjugated polymer comprises one or more repeating units of formula II1 or II2 wherein a+b+c+d≥1.

Further preferably the conjugated polymer comprises one or more repeating units of formula II1 wherein b=1 and a=c=d=0 and one or more repeating units of formula II3 wherein a=b=1 and c=d=0.

Further preferably the conjugated polymer comprises two or more distinct repeating units of formula II1 wherein b=1 and a=c=d=0.

Further preferably the conjugated polymer consists of repeating units of formula II1 wherein a=b=c=d=0 (homopolymers of units U).

Further preferably at least one of Ar¹, Ar², Ar³ and Ar⁴ is an arylene or heteroarylene group as being defined in formula II1 and having electron donor property.

Very preferred are repeating units selected from the following formulae.

wherein R¹ is as defined above and below, X has on each occurrence identically or differently one of the meanings of X¹ as given above and below, Y is as defined above and below, t is 1, 2, 3 or 4, preferably 1 or 2, and R², R³ and R⁴ have independently of each other and on each occurrence identically or differently one of the meanings given for L.

In formulae R1-R11 X is preferably O or S, very preferably O.

In formulae R1-R11 Y is preferably O, S or

with R being as defined above.

Further preferably the conjugated polymer according to the present invention is selected of formula III: *

(A)_(x)-(B)_(y)

_(n)*  III

wherein

-   -   A is a unit of formula I, II1, II2 or R1-R11 as defined above         and below,     -   B is a unit of formula I, II1, II2, II3 or R1-R11 as defined         above and below which is different from A,     -   x is >0 and ≤1,     -   y is ≥0 and <1,     -   x+y is 1, and     -   n is an integer ≥5.

Further preferably the conjugated polymer according to the present invention is selected from the following formulae

wherein

X¹, X², Y and R¹ have the meanings of formula I or one of the preferred meanings given above and below,

X^(1a) has one of the meanings given for X¹,

X^(2a) has one of the meanings given for X¹,

Y^(a) has one of the meanings given for Y,

R^(1a) has one of the meanings given for R¹,

Ar², Ar³, Ar⁴, a, b, c and d have the meanings of formula II1 or one of the preferred meanings given above and below,

x, y and n have the meanings of formula III or one of the preferred meanings given above and below,

preferably Ar³ is selected from arylene or heteroarylene units as described above and below having electron donor properties, and

in formula III3 and III5 preferably at least one of X¹, X², Y and R¹ is different from its corresponding radical X^(1a), X^(2a) and R^(1a), respectively.

In the polymers of formula III and III1-III5, x and y denote the mole fraction of repeating units A and B, respectively, and n denotes the degree of polymerisation or total number of repeating units A and B. These formulae include block copolymers, random or statistical copolymers and alternating copoymers of A and B, as well as homopolymers of A for the case when x>0 and y=0.

In the polymers of formula III and III1-III5, x is preferably from 0.1 to 0.9, very preferably from 0.3 to 0.7.

In the polymers of formula III and III1-III5, y is preferably from 0.1 to 0.9, very preferably from 0.3 to 0.7.

In the polymers according to the present invention, the total number of repeating units n is preferably from 2 to 10,000. The total number of repeating units n is preferably ≥5, very preferably ≥10, most preferably ≥50, and preferably ≤500, very preferably ≤1,000, most preferably ≤2,000, including any combination of the aforementioned lower and upper limits of n.

The polymers of the present invention include homopolymers and copolymers, like statistical or random copolymers, alternating copolymers and block copolymers, as well as combinations thereof.

Further preferably the conjugated polymer according to the present invention is selected of formula IV R⁵-chain-R⁶  IV

wherein “chain” denotes a polymer chain selected of formulae III, III1-III5, and P1-P32, and R⁵ and R⁶ have independently of each other one of the meanings of R¹ or L as defined above, or denote, independently of each other, H, F, Br, Cl, I, —CH₂Cl, —CHO, —CR′═CR″₂, —SiR′R″R′″, —SiR′X′X″, —SiR′R″X′, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂, —O—SO₂—R′, —C≡CH, —C≡C—SiR′₃, —ZnX′ or an endcap group, X′ and X″ denote halogen, R′, R″ and R′″ have independently of each other one of the meanings of R⁰ given in formula I, and preferably denote alkyl with 1 to 12 C atoms, and two of R′, R″ and R′″ may also form a cyclosilyl, cyclostannyl, cycloborane or cycloboronate group with 2 to 20 C atoms together with the respective hetero atom to which they are attached.

Preferred endcap groups R⁵ and R⁶ are H, C₁₋₄₀ alkyl, or optionally substituted C₆₋₁₂ aryl or C₂₋₁₀ heteroaryl, very preferably H or phenyl.

A further preferred embodiment of the present invention relates to a monomer of formula V1 or V2 R⁷—(Ar¹)_(a)—U—(Ar²)_(b)—(Ar³)_(c)—(Ar⁴)_(d)—R⁸  V1 R⁷—(Ar¹)_(a)—(Ar²)_(b)—U—(Ar³)_(c)—(Ar⁴)_(d)—R⁸  V2

wherein U, Ar¹⁻⁴, a, b, c and d have the meanings of formula II1, or one of the preferred meanings as described above and below, and R⁷ and R⁸ are independently of each other selected from the group consisting of H, which is preferably an activated C—H bond, Cl, Br, I, O-tosylate, O-triflate, O-mesylate, O-nonaflate, —SiMe₃, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂, —CZ³═C(Z³)₂, —C≡CH, —C≡CSi(Z¹)₃, —ZnX⁰, Mg—X⁰ and —Sn(Z⁴)₃, wherein X⁰ is halogen, preferably Cl, Br or I, Z¹⁻⁴ are selected from the group consisting of alkyl and aryl, preferably C₁₋₁₀ alkyl and C₆₋₁₂ aryl, each being optionally substituted, and two groups Z² may also form a cycloboronate group having 2 to 20 C atoms together with the B- and O-atoms, and wherein at least one of R⁷ and R⁸ is different from H, and preferably both of R¹ and R² are different from H.

Very preferred are monomers of formula V1 and V2 and their subformulae wherein a+b+c+d≥1.

Further preferred are monomers of formula V1 and its subformulae wherein a+b+c+d=0.

Further preferred are monomers selected from the following formulae R⁷—Ar¹—U—Ar²—R⁸  V1a R⁷—U—R⁸  V1b R⁷—Ar¹—U—R⁸  V1c R⁷—U—Ar²—R⁸  V1d

wherein U, Ar¹, Ar², R⁷ and R⁸ are as defined in formula V1.

Further preferred are monomers of formula V3 R⁷—U*—R⁸  V3

wherein U* is a unit selected from formula R1-R11 as defined above and R⁷ and R⁸ are as defined in formula V1.

Very preferred are monomers of formula V1, V2 and V3 and their subformulae wherein R⁷ and R⁸ are selected from Br, B(OZ²)₂, Mg—X⁰ and Sn(Z⁴)₃.

A further preferred embodiment of the present invention relates to a small molecule or oligomer of formula VI

wherein the individual radicals, independently of each other and on each occurrence identically or differently, have the following meanings

Ar²¹⁻²⁸ are one of the meanings given for Ar¹ in formula II1 or one of its preferred meanings given above and below, or a unit of formula I as defined above and below, or —CY¹═CY²—,

-   -   Y¹, Y² H, F, Cl or CN,     -   R^(1t, 2t) H, F, Cl, Br, —CN, —CF₃, R*, —CF₂—R*, —O—R*, —S—R*,         —SO₂—R*, —SO₃—R*,—C(═O)—R*, —C(═S)—R*, —C(═O)—CF₂—R*,         —C(═O)—OR*, —C(═S)—OR*, —O—C(═O)—R*, —O—C(═S)—R*, —C(═O)—SR*,         —S—C(═O)—R*, —C(═O)NR*R**, —NR*—C(═O)—R*, —NHR*, —NR*R**,         —CR*═CR*R**, —C≡C—R*, —C≡C—SiR*R**R***, —SiR*R**R***,         —CH═C(CN)—C(═O)—OR*, —CH═C(CO—OR*)₂, —CH═C(CO—NR*R**)₂,         —CH═C(CN)(Ar⁹),

-   -   Ar^(9,10) aryl or heteroaryl, each having from 4 to 30 ring         atoms, optionally containing fused rings and being unsubstituted         or substituted with one or more groups L as defined in formula         I,     -   R*, R**, R*** alkyl with 1 to 20 C atoms which is         straight-chain, branched or cyclic, and is unsubstituted, or         substituted with one or more F or Cl atoms or CN groups, or         perfluorinated, and in which one or more C atoms are optionally         replaced by —O—, —S—, —C(═O)—, —C(═S)—, —SiR⁰R⁰⁰—, —NR⁰R⁰⁰—,         —CHR⁰═CR⁰⁰— or —C≡C— such that O- and/or S-atoms are not         directly linked to each other,     -   R⁰, R⁰⁰ H or straight-chain or branched alkyl with 1 to 20,         preferably 1 to 12 C atoms that is optionally fluorinated,     -   a-h 0 or 1, preferably with at least one of a-h being 1,     -   m 1, 2 or 3,     -   L one of the meanings given above and below,     -   r 0, 1, 2, 3 or 4,

with the proviso that if a+b+c+d+e+f+g+h=0 and X¹, X² and Y are O, then at least one of R^(1t) and R^(2t) is different from H.

Especially preferred are small molecules of formula VI1 R^(1t)—U*—R^(2t)  VI1

wherein U* is a unit selected from formulae R1-R11 as defined above, and R^(1t) and R^(2t) have the meanings given in formula VI, and preferably denote H, F, R* or OR*.

Further preferred are repeating units, monomers, oligomers, polymers and small molecules of formulae II1, II2, III, III1-III5, IV, V1, V2, V1a-V1d, VI and their subformulae wherein one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene, preferably having electron donor properties, selected from the group consisting of the following formulae

wherein R¹¹, R¹², R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, and R¹⁸ independently of each other denote H or have one of the meanings of L as defined above and below.

Preferred donor units are selected from formulae D1, D7, D10, D11, D19, D22, D29, D30, D35, D36, D44, D55, D84, D87, D88, D89, D93, D106, D111, D140, D141 and D146, wherein preferably at least one of R¹¹, R¹², R¹³ and R¹⁴ is different from H.

Further preferred are repeating units, monomers, oligomers, polymers and small molecules of formulae II1, II2, III, III1-III5, IV, V1, V2, V1a-V1d, VI and their subformulae wherein one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene, preferably having electron acceptor properties, selected from the group consisting of the following formulae

wherein R¹¹, R¹², R¹³, R¹⁴, R¹⁵ and R¹⁶ independently of each other denote H or have one of the meanings of L as defined above and below.

Preferred acceptor units are selected from formulae A1, A6, A7, A15, A16, A20, A74, A88, A92 or A98 wherein preferably at least one of R¹¹, R¹², R¹³ and R¹⁴ is different from H.

Further preferred are repeating units, monomers, oligomers, polymers and small molecules of formulae II1, II2, III, III1-III5, IV, V1, V2, V1a-V1d, VI and their subformulae wherein one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene selected from the group consisting of the following formulae

wherein R¹¹ and R¹² independently of each other denote H or have one of the meanings of L as defined above and below.

Very preferred are units selected from formulae Sp1, Sp6, Sp13, wherein preferably one of R¹¹ and R¹² is H or both R¹¹ and R¹² are H.

Further preferred are repeating units, monomers and polymers of formulae II1, II2, III, III1-III5, IV, V1, V2, V1a-V1 d and their subformulae wherein

-   -   a) one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or         heteroarylene, preferably having electron donor properties,         selected from the group consisting of the formulae D1-D145, very         preferably of the formulae D1, D7, D10, D11, D19, D22, D29, D30,         D35, D36, D44, D55, D84, D87, D88, D89, D93, D106, D111, D140,         D141 and D146, and/or     -   b) one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or         heteroarylene, preferably having electron acceptor properties,         selected from the group consisting of the formulae A1-A98, very         preferably of the formulae A1, A6, A7, A15, A16, A20, A74, A88,         A92 and A98, and     -   c) one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or         heteroarylene selected from the group consisting of the formulae         Sp1-Sp15, very preferably of the formulae Sp1, Sp6 and Sp13.

Further preferred are polymers of formula III3 and III5 wherein Ar¹ and Ar² have the same meaning and are selected from formulae D1, D7, D10, D11, D19, D22, D29, D30, D35, D36, D44, D55, D84, D87, D88, D89, D93, D106, D111, D140, D141 and D146, and R¹ and R² denote R or —OR, and R³ and R⁴ denote C(═O)—R or C(═O)—OR with R being as defined above.

Further preferred are oligomers and small molecules of formula VI wherein Ar²¹⁻²⁸ are selected from the following groups

-   -   a) the group consisting of the formulae D1-D145, very preferably         of the formulae D1, D7, D10, D11, D19, D22, D29, D30, D35, D36,         D44, D55, D84, D87, D88, D89, D93, D106, D111, D140, D141 and         D146,     -   b) the group consisting of the formulae A1-A98, very preferably         of the formulae A1, A6, A7, A15, A16, A20, A74, A88, A92 or A98,     -   c) the group consisting of the formulae Sp1-Sp15, very         preferably of the formulae Sp1, Sp6 and Sp13.

Very preferred is a conjugated polymer selected from the following formulae:

wherein R¹, x, y and n are as defined above and below, 0<z<1, x+y+z=1, X has on each occurrence identically or differently one of the meanings of X¹ as given above and below, Y is as defined above and below, t is 1, 2, 3 or 4, preferably 1 or 2, and R², R³ and R⁴ have independently of each other and on each occurrence identically or differently one of the meanings given for L.

In formulae P1-P32 X is preferably O or S, very preferably O.

In formulae P1-P32 Y is preferably O, S,

with R being as defined above.

Further preferred units, monomers, oligomers, polymers and small molecules of formulae I, II1, II2, III, III1-III5, IV, V1, V2, V1a-V1d, VI, R1-R11, P1-P32 and their subformulae are selected from the following embodiments, including any combination thereof:

-   -   X¹ and X² denote O,     -   X¹ and X² denote S,     -   one of X¹ and X² denotes O and the other denotes S,     -   Y is O,     -   Y is S,     -   Y is CU¹U²,     -   X¹, X² and Y are not at the same time O,     -   if X¹ and X² are O then Y is S or CU¹U²,     -   in the units of formula I at least one of the groups attached to         the 1- and 4-positions of the benzene ring is different from H,     -   in the units of formula I both groups attached to the 1- and         4-positions of the benzene ring are different from H,     -   R¹ is selected from alkyl, alkoxy or thiaalkyl, all of which are         straight-chain or branched, have 1 to 25, preferably 1 to 18 C         atoms, and are optionally fluorinated,     -   R¹ is selected from —C(═O)—R^(n), —C(═O)—OR^(n), —C(═O)—NHR^(n)         and —C(═O)—NR^(n)R^(m), wherein R^(m) and R^(n) are         independently of each other straight-chain or branched alkyl         with 1 to 25, preferably 1 to 18 C atoms that is optionally         fluorinated,     -   R¹ is cyclic alkyl with 4 to 20 ring atoms, wherein one or more         CH₂ groups are optionally replaced by O, S, NR⁰, C(═O), (C═S),         CY¹═CY² or CR⁰═CR⁰⁰, and which is unsubstituted or substituted         by one or more groups L as defined in formula I,     -   R¹ is selected from the group consisting of aryl, heteroaryl,         aryloxy, heteroaryloxy, arylalkyl and heteroarylalkyl, each of         which has 4 to 20 ring atoms and optionally contains fused rings         and is unsubstituted or substituted by one or more groups L as         defined in formula I,     -   R is straight-chain or branched alkyl with 1 to 25, preferably 1         to 18 C atoms which is optionally fluorinated,     -   R is cyclic alkyl with 4 to 20 ring atoms, wherein one or more         CH₂ groups are optionally replaced by O, S, NR⁰, C(═O), (C═S),         CY¹═CY² or CR⁰═CR⁰⁰, and which is unsubstituted or substituted         by one or more groups L as defined in formula I,     -   R is aryl, heteroaryl, arylalkyl or heteroarylalkyl, each of         which has 4 to 20 ring atoms, optionally contains fused rings,         and is unsubstituted or substituted by one or more groups L as         defined in formula I,     -   U¹ and U² denote CN,     -   U¹ and U² denote C(═O)R or C(═O)OR, wherein R has one of the         meanings given above and below, and is preferably straight-chain         or branched alkyl with 1 to 25, preferably 1 to 18 C atoms which         is optionally fluorinated,     -   L is selected from alkyl, alkoxy or thiaalkyl, all of which are         straight-chain or branched, have 1 to 25, preferably 1 to 18 C         atoms, and are optionally fluorinated,     -   L is selected from —C(═O)—R^(n), —C(═O)—OR^(n), —C(═O)—NHR^(n)         and —C(═O)—NR^(n)R^(m), wherein R^(m) and R^(n) are         independently of each other straight-chain or branched alkyl         with 1 to 25, preferably 1 to 18 C atoms that is optionally         fluorinated,     -   L is halogen, preferably F or Cl,     -   L is CN, F or Cl,     -   R⁷ and R⁸ are different from H,     -   R⁷ and R⁸ denote Br, B(OZ²)₂ or Sn(Z⁴)₃, wherein Z² and Z⁴ are         as defined in formula V1.

The polymers according to the present invention can be prepared for example by copolymerising one or more monomers of formula V1, V2, V3 or V1a-V1d with each other or with one or monomers of the following formulae in an aryl-aryl coupling reaction R⁷—Ar¹—R⁸  MI R⁷—Ar²—R⁸  MII R⁷—Ar^(a)—R⁸  MIII R⁷—Ar⁴—R⁸  MIV

wherein Ar¹⁻⁴, R⁷ and R⁸ have the meanings given in formula II2 and V1 or one of the preferred meanings given above and below.

The polymer according to the present invention can be synthesized according to or in analogy to methods that are known to the skilled person and are described in the literature. Other methods of preparation can be taken from the examples.

For example, the polymer can be suitably prepared by aryl-aryl coupling reactions, such as Yamamoto coupling, C—H activation coupling, Suzuki coupling, Stille coupling, Sonogashira coupling, Heck coupling or Buchwald coupling. Suzuki coupling, Stille coupling and Yamamoto coupling are especially preferred. The monomers which are polymerised to form the repeat units of the polymers can be prepared according to methods which are known to the person skilled in the art.

Preferably the polymer is prepared from monomers selected from formulae V1, V2, V3, V1a-d and MI-MIV as described above.

Another aspect of the invention is a process for preparing a polymer by coupling one or more identical or different monomers selected from formulae V1, V2, V3, V1a-d with each other and/or with one or more co-monomers, preferably selected from formulae MI-MIV, in a polymerisation reaction, preferably in an aryl-aryl coupling reaction.

Preferred aryl-aryl coupling and polymerisation methods used in the processes described above and below are Yamamoto coupling, Kumada coupling, Negishi coupling, Suzuki coupling, Stille coupling, Sonogashira coupling, Heck coupling, C—H activation coupling, Ullmann coupling or Buchwald coupling. Especially preferred are Suzuki coupling, Negishi coupling, Stille coupling and Yamamoto coupling. Suzuki coupling is described for example in WO 00/53656 A1. Negishi coupling is described for example in J. Chem. Soc., Chem. Commun., 1977, 683-684. Yamamoto coupling is described in for example in T. Yamamoto et al., Prog. Polym. Sci., 1993, 17, 1153-1205, or WO 2004/022626 A1.Stille coupling is described for example in Z. Bao et al., J. Am. Chem. Soc., 1995, 117, 12426-12435. C—H activation is described for example for example in M. Leclerc et al, Angew. Chem. Int. Ed. 2012, 51, 2068-2071. For example, when using Yamamoto coupling, monomers having two reactive halide groups are preferably used. When using Suzuki coupling, monomers having two reactive boronic acid or boronic acid ester groups or two reactive halide groups are preferably used. When using Stille coupling, monomers having two reactive stannane groups or two reactive halide groups are preferably used. When using Negishi coupling, monomers having two reactive organozinc groups or two reactive halide groups are preferably used. When synthesizing a linear polymer by C—H activation polymerisation, preferably a monomer as described above is used wherein at least one reactive group is an activated hydrogen bond.

Preferred catalysts, especially for Suzuki, Negishi or Stille coupling, are selected from Pd(0) complexes or Pd(II) salts. Preferred Pd(0) complexes are those bearing at least one phosphine ligand such as Pd(Ph₃P)₄. Another preferred phosphine ligand is tris(ortho-tolyl)phosphine, i.e. Pd(o-Tol₃P)₄. Preferred Pd(II) salts include palladium acetate, i.e. Pd(OAc)₂ or trans-di(μ-acetato)-bis[o-(di-o-tolylphosphino)benzyl]dipalladium(II). Alternatively the Pd(0) complex can be prepared in situ by mixing a Pd(0) dibenzylideneacetone complex, for example tris(dibenzyl-ideneacetone)dipalladium(0), bis(dibenzylideneacetone)palladium(0), or Pd(II) salts e.g. palladium acetate, with a phosphine ligand, for example triphenylphosphine, tris(ortho-tolyl)phosphine, tris(o-methoxyphenyl)phosphine, tri(tert-butyl)phosphine or 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl. Suzuki polymerisation is performed in the presence of a base, for example sodium carbonate, potassium carbonate, cesium carbonated, lithium hydroxide, potassium phosphate or an organic base such as tetraethylammonium carbonate or tetraethylammonium hydroxide. Yamamoto polymerisation employs a Ni(0) complex, for example bis(1,5-cyclooctadienyl) nickel(0).

Suzuki, Stille or C—H activation coupling polymerisation may be used to prepare homopolymers as well as statistical, alternating and block random copolymers. Statistical, random block copolymers or block copolymers can be prepared for example from the above monomers, wherein one of the reactive groups is halogen and the other reactive group is a C—H activated bond, boronic acid, boronic acid derivative group or and alkylstannane. The synthesis of statistical, alternating and block copolymers is described in detail for example in WO 03/048225 A2 or WO 2005/014688 A2.

As alternatives to halogen as described above, leaving groups of formula —O—SO₂Z¹ can be used wherein Z¹ is as defined above. Particular examples of such leaving groups are tosylate, mesylate and triflate.

Preferred polymerisation conditions lead to alternating polymers which are particularly preferred for OTFT application, whereas statistical block co-polymers are prepared preferably for OPV and OPD application. Preferred polycondensation are Suzuki coupling, Stille coupling, Sonogashira coupling, Heck coupling or Buchwald coupling, Negishi coupling or C—H activation coupling where the first set of reactive groups is composed of —Cl, —Br, —I, O-tosylate, O-triflate, O-mesylate and O-nonaflate and the second set of reactive groups is composed of —H, —SiR₂F, —SiRF₂, —B(OR)₂, —CR═CHR', —C≡CH, —ZnX, —MgX and —Sn(R)₃. If a Yamamoto coupling reaction is used to prepare the polymer, the reactive monomer ends are both composed independently of —Cl, —Br, —I, O-tosylate, O-triflate, O-mesylate and O-nonaflate.

Suitable and preferred methods for preparing compounds according to the present invention are illustrated in the reaction schemes below, wherein R, R′, R¹, R² and Ar¹ are as defined above. The compounds not shown, e.g. wherein in the units of formula I X is S, or Y is O, S or CU¹U², can be made in analogy thereto.

The DTPI units can be synthesized for example by reacting 3,6-diaryl-4,5-dichlorophthalimide with the corresponding dithiolate to form the [4,5-d] fused dithiol rings as exemplarily illustrated in Scheme 1. The 3,6-diaryl-4,5-dichlorophthalimides can be made from cross-couplings of 3,6-bromo-4,5-dichlorophthalimide with arylboronic acids, arylboronic esters or arylstannanes.

Conjugated polymers and co-polymers, including alternating co-polymers and statistical block co-polymers can be made by the methods described above. Particularly, conjugated polymer can be made by Pd catalysed direct arylation polymerisation with a dibromo counterpart (M. Wakioka, et al., Macromol., 2015, 48, 8382) or Pd catalysed polycondensations methods such as Yamamoto reaction (Yamamoto et al., Bull., Chem. Soc. Jpn., 1978, 51(7), 2091; Yamamo to et al., Macromolecules, 1992, 25(4), 1214), Suzuki-Miyaura reaction (Miyaura et al., Chem. Rev., 1995, 95, 2457) and Stille reaction (Bao et al., J. Am., Chem., Soc., 1995, 117(50), 12426) using the terminally brominated derivatives. Some preferred polymerization reactions are exemplarily illustrated represented in Scheme 2.

The novel polymers shown in Scheme 2 are a further subject of the invention.

The synthesis of oligomers and small molecules based on the DTPI core is exemplarily illustrated in Scheme 3. Alternatively these compounds can be obtained via a convergent synthesis strategy as shown in Scheme 4. Therein Y and R¹ are as defined in formula I, X₁═Br and X₂═SnR'₃ or B(OR′)₂ or X₁═SnR′₃ and X₂═Br or X₁═B(OR′)₂ and X₂═Br, Ar₁₋₈ correspond to Ar¹⁻⁸ as defined in formula VI, and Ar₅—Ar₆—Ar₇—Ar₈—R² _(end) is identical to Ar₄—Ar₃—Ar₂—Ar₁—R¹ _(end) and R¹ _(end) and R² _(end) correspond to R^(1t) and R^(2t) in formula VI.

Alternatively asymmetric small molecules based on DTPI can be obtained via a convergent synthesis strategy as shown in Scheme 5, wherein the individual radicals are as defined in Scheme 3 and 4.

The synthesis of asymmetric compounds containing multiple DTPI units via a convergent synthesis strategy is shown in Scheme 6, wherein the individual radicals are as defined in Scheme 3, and 1<n≤3.

Further substitution can be added to the DTPI core at the R^(1,2) _(end) substitution after the DTPI core compounds have been prepared as shown in Scheme 7, wherein the individual radicals are as defined in Scheme 6.

The novel methods of preparing a compound, monomer or polymer as described above and below, and the novel monomers and intermediates used therein, are further aspects of the invention.

The polymer according to the present invention can also be used in mixtures or polymer blends, for example together with monomeric compounds or together with other polymers having charge-transport, semiconducting, electrically conducting, photoconducting and/or light-emitting semiconducting properties, or for example with polymers having hole blocking, electron blocking properties for use as interlayers, charge blocking layers, charge transporting layer in OLED devices, OPV devices or pervorskite based solar cells. Thus, another aspect of the invention relates to a polymer blend comprising one or more polymers according to the present invention and one or more further polymers having one or more of the above-mentioned properties. These blends can be prepared by conventional methods that are described in prior art and known to the skilled person. Typically the polymers are mixed with each other or dissolved in suitable solvents and the solutions combined.

Another aspect of the invention relates to a formulation comprising one or more polymers, polymer blends or mixtures as described above and below and one or more organic solvents.

Preferred solvents are aliphatic hydrocarbons, chlorinated hydrocarbons, aromatic hydrocarbons, ketones, ethers and mixtures thereof. Additional solvents which can be used include 1,2,4-trimethylbenzene, 1,2,3,4-tetramethyl benzene, pentylbenzene, mesitylene, cumene, cymene, cyclohexylbenzene, diethylbenzene, tetralin, decalin, 2,6-lutidine, 2-fluoro-m-xylene, 3-fluoro-o-xylene, 2-chlorobenzotrifluoride, N,N-dimethylformamide, 2-chloro-6-fluorotoluene, 2-fluoroanisole, anisole, 2,3-dimethylpyrazine, 4-fluoroanisole, 3-fluoroanisole, 3-trifluoro-methylanisole, 2-methylanisole, phenetol, 4-methylanisole, 3-methylanisole, 4-fluoro-3-methylanisole, 2-fluorobenzonitrile, 4-fluoroveratrol, 2,6-dimethylanisole, 3-fluorobenzo-nitrile, 2,5-dimethylanisole, 2,4-dimethylanisole, benzonitrile, 3,5-dimethylanisole, N,N-dimethylaniline, ethyl benzoate, 1-fluoro-3,5-dimethoxy-benzene, 1-methylnaphthalene, N-methylpyrrolidinone, 3-fluorobenzotrifluoride, benzotrifluoride, dioxane, trifluoromethoxy-benzene, 4-fluorobenzotrifluoride, 3-fluoropyridine, toluene, 2-fluoro-toluene, 2-fluorobenzotrifluoride, 3-fluorotoluene, 4-isopropylbiphenyl, phenyl ether, pyridine, 4-fluorotoluene, 2,5-difluorotoluene, 1-chloro-2,4-difluorobenzene, 2-fluoropyridine, 3-chlorofluoro-benzene, 1-chloro-2,5-difluorobenzene, 4-chlorofluorobenzene, chloro-benzene, o-dichlorobenzene, 2-chlorofluorobenzene, p-xylene, m-xylene, o-xylene or mixture of o-, m-, and p-isomers. Solvents with relatively low polarity are generally preferred. For inkjet printing solvents and solvent mixtures with high boiling temperatures are preferred. For spin coating alkylated benzenes like xylene and toluene are preferred.

Examples of especially preferred solvents include, without limitation, dichloromethane, trichloromethane, tetrachloromethane, chlorobenzene, o-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,8-diiodooctane, 1-chloronaphthalene, 1,8-octane-dithiol, anisole, 2,5-di-methylanisole, 2,4-dimethylanisole, toluene, o-xylene, m-xylene, p-xylene, mixture of o-, m-, and p-xylene isomers, 1,2,4-trimethylbenzene, mesitylene, cyclohexane, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, tetraline, decaline, indane, 1-methyl-4-(1-methylethenyl)-cyclohexene (d-Limonene), 6,6-dimethyl-2-methylenebicyclo[3.1.1]heptanes (β-pinene), methyl benzoate, ethyl benzoate, nitrobenzene, benzaldehyde, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, morpholine, acetone, methylethylketone, ethyl acetate, n-butyl acetate, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide and/or mixtures thereof.

The concentration of the polymers in the solution is preferably 0.1 to 10% by weight, more preferably 0.5 to 5% by weight. Optionally, the solution also comprises one or more binders to adjust the rheological properties, as described for example in WO 2005/055248 A1.

After the appropriate mixing and ageing, solutions are evaluated as one of the following categories: complete solution, borderline solution or insoluble. The contour line is drawn to outline the solubility parameter-hydrogen bonding limits dividing solubility and insolubility. ‘Complete’ solvents falling within the solubility area can be chosen from literature values such as published in “Crowley, J. D., Teague, G. S. Jr and Lowe, J. W. Jr., Journal of Paint Technology, 1966, 38 (496), 296”. Solvent blends may also be used and can be identified as described in “Solvents, W. H. Ellis, Federation of Societies for Coatings Technology, p 9-10, 1986”. Such a procedure may lead to a blend of ‘non’ solvents that will dissolve both the polymers of the present invention, although it is desirable to have at least one true solvent in a blend.

The polymer according to the present invention can also be used in patterned OSC layers in the devices as described above and below. For applications in modern microelectronics it is generally desirable to generate small structures or patterns to reduce cost (more devices/unit area), and power consumption. Patterning of thin layers comprising a polymer according to the present invention can be carried out for example by photolithography, electron beam lithography or laser patterning.

For use as thin layers in electronic or electrooptical devices the polymers, polymer blends or formulations of the present invention may be deposited by any suitable method. Liquid coating of devices is more desirable than vacuum deposition techniques. Solution deposition methods are especially preferred. The formulations of the present invention enable the use of a number of liquid coating techniques. Preferred deposition techniques include, without limitation, dip coating, spin coating, ink jet printing, nozzle printing, letter-press printing, screen printing, gravure printing, doctor blade coating, roller printing, reverse-roller printing, offset lithography printing, dry offset lithography printing, flexographic printing, web printing, spray coating, curtain coating, brush coating, slot dye coating or pad printing.

Ink jet printing is particularly preferred when high resolution layers and devices needs to be prepared. Selected formulations of the present invention may be applied to prefabricated device substrates by ink jet printing or microdispensing. Preferably industrial piezoelectric print heads such as but not limited to those supplied by Aprion, Hitachi-Koki, InkJet Technology, On Target Technology, Picojet, Spectra, Trident, Xaar may be used to apply the organic semiconductor layer to a substrate. Additionally semi-industrial heads such as those manufactured by Brother, Epson, Konica, Seiko Instruments Toshiba TEC or single nozzle microdispensers such as those produced by Microdrop and Microfab may be used.

In order to be applied by ink jet printing or microdispensing, the polymers should be first dissolved in a suitable solvent. Solvents must fulfil the requirements stated above and must not have any detrimental effect on the chosen print head. Additionally, solvents should have boiling points >100° C., preferably >140° C. and more preferably >150° C. in order to prevent operability problems caused by the solution drying out inside the print head. Apart from the solvents mentioned above, suitable solvents include substituted and non-substituted xylene derivatives, di-C₁₋₂-alkyl formamide, substituted and non-substituted anisoles and other phenol-ether derivatives, substituted heterocycles such as substituted pyridines, pyrazines, pyrimidines, pyrrolidinones, substituted and non-substituted N,N-di-C₁₋₂-alkylanilines and other fluorinated or chlorinated aromatics.

A preferred solvent for depositing a polymer according to the present invention by ink jet printing comprises a benzene derivative which has a benzene ring substituted by one or more substituents wherein the total number of carbon atoms among the one or more substituents is at least three. For example, the benzene derivative may be substituted with a propyl group or three methyl groups, in either case there being at least three carbon atoms in total. Such a solvent enables an ink jet fluid to be formed comprising the solvent with the compound or polymer, which reduces or prevents clogging of the jets and separation of the components during spraying. The solvent(s) may include those selected from the following list of examples: dodecylbenzene, 1-methyl-4-tert-butylbenzene, terpineol, limonene, isodurene, terpinolene, cymene, diethylbenzene. The solvent may be a solvent mixture, that is a combination of two or more solvents, each solvent preferably having a boiling point >100° C., more preferably >140° C. Such solvent(s) also enhance film formation in the layer deposited and reduce defects in the layer.

The ink jet fluid (that is mixture of solvent, binder and semiconducting compound) preferably has a viscosity at 20° C. of 1-100 mPa·s, more preferably 1-50 mPa·s and most preferably 1-30 mPa·s.

The polymers, polymer blends, mixtures and formulations according to the present invention can additionally comprise one or more further components or additives selected for example from surface-active compounds, lubricating agents, wetting agents, dispersing agents, hydrophobing agents, adhesive agents, flow improvers, defoaming agents, deaerators, diluents which may be reactive or non-reactive, auxiliaries, colourants, dyes or pigments, sensitizers, stabilizers, nanoparticles or inhibitors.

The polymers, polymer blends and mixtures according to the present invention are useful as charge transport, semiconducting, electrically conducting, photoconducting or light emitting material in optical, electrooptical, electronic, electroluminescent or photoluminescent components or devices. In these devices, a polymer, polymer blend or mixture of the present invention is typically applied as a thin layer or film.

Thus, the present invention also provides the use of the polymer, polymer blend, mixture or layer in an electronic device. The formulation may be used as a high mobility semiconducting material in various devices and apparatus. The formulation may be used, for example, in the form of a semiconducting layer or film. Accordingly, in another aspect, the present invention provides a semiconducting layer for use in an electronic device, the layer comprising a polymer, mixture or polymer blend according to the invention. The layer or film may be less than about 30 microns. For various electronic device applications, the thickness may be less than about 1 micron thick. The layer may be deposited, for example on a part of an electronic device, by any of the aforementioned solution coating or printing techniques.

The invention additionally provides an electronic device comprising a polymer, polymer blend, mixture or organic semiconducting layer according to the present invention. Especially preferred devices are OTFTs, TFTs, ICs, logic circuits, capacitors, RFID tags, OLEDs, OLETs, OPEDs, OPVs, OPDs, solar cells, laser diodes, photoconductors, photodetectors, electrophotographic devices, electrophotographic recording devices, organic memory devices, sensor devices, charge injection layers, Schottky diodes, planarising layers, antistatic films, conducting substrates and conducting patterns.

Especially preferred electronic device are OTFTs, OLEDs, OPV and OPD devices, in particular bulk heterojunction (BHJ) OPV devices. In an OTFT, for example, the active semiconductor channel between the drain and source may comprise the layer of the invention. As another example, in an OLED device, the charge (hole or electron) injection or transport layer may comprise the layer of the invention.

For use in OPV or OPD devices the polymer according to the present invention is preferably used in a formulation that comprises or contains, more preferably consists essentially of, very preferably exclusively of, one or more p-type (electron donor) semiconductor and one or more n-type (electron acceptor) semiconductor. The p-type semiconductor is constituted of a least one polymer according to the present invention. The n-type semiconductor can be an inorganic material such as zinc oxide (ZnO_(x)), zinc tin oxide (ZTO), titanium oxide (TiO_(x)), molybdenum oxide (MoO_(x)), nickel oxide (NiO_(x)), or cadmium selenide (CdSe), or an organic material such as graphene or a fullerene, a conjugated polymer or substituted fullerene, for example a (6,6)-phenyl-butyric acid methyl ester derivatized methano C₆₀ fullerene, also known as “PCBM-C₆₀” or “C₆₀PCBM”, as disclosed for example in Science 1995, 270, 1789 and having the structure shown below, or structural analogous compounds with e.g. a C₇₀ fullerene group or an organic polymer (see for example Coakley, K. M. and McGehee, M. D. Chem. Mater. 2004, 16, 4533).

Preferably the polymer according to the present invention is blended with an n-type semiconductor such as a fullerene or substituted fullerene of formula XII to form the active layer in an OPV or OPD device wherein,

-   -   C_(n) denotes a fullerene composed of n carbon atoms, optionally         with one or more atoms trapped inside,     -   Adduct¹ is a primary adduct appended to the fullerene C_(n) with         any connectivity,     -   Adduct² is a secondary adduct, or a combination of secondary         adducts, appended to the fullerene C_(n) with any connectivity,     -   k is an integer ≥1,     -   and     -   l is 0, an integer ≥1, or a non-integer >0.

In the formula XII and its subformulae, k preferably denotes 1, 2, 3 or, 4, very preferably 1 or 2.

The fullerene C_(n) in formula XII and its subformulae may be composed of any number n of carbon atoms Preferably, in the compounds of formula XII and its subformulae the number of carbon atoms n of which the fullerene C_(n) is composed is 60, 70, 76, 78, 82, 84, 90, 94 or 96, very preferably 60 or 70.

The fullerene C_(n) in formula XII and its subformulae is preferably selected from carbon based fullerenes, endohedral fullerenes, or mixtures thereof, very preferably from carbon based fullerenes.

Suitable and preferred carbon based fullerenes include, without limitation, (C_(60-Ih))[5,6]fullerene, (C_(70-D5h))[5,6]fullerene, (C_(76-D2*))[5,6]fullerene, (C_(84-D2*))[5,6]fullerene, (C_(84-D2d))[5,6]fullerene, or a mixture of two or more of the aforementioned carbon based fullerenes.

The endohedral fullerenes are preferably metallofullerenes. Suitable and preferred metallofullerenes include, without limitation, La@C₆₀, La@C₈₂, Y@C₈₂, Sc₃N@C₈₀, Y₃N@C₈₀, Sc₃C₂@C₈₀ or a mixture of two or more of the aforementioned metallofullerenes.

Preferably the fullerene C_(n) is substituted at a [6,6] and/or [5,6] bond, preferably substituted on at least one [6,6] bond.

Primary and secondary adduct, named “Adduct” in formula XII and its subformulae, is preferably selected from the following formulae

wherein C_(n) is as defined in formula XII,

-   -   Ar^(S1), Ar^(S2) denote, independently of each other, an arylene         or heteroarylene group with 5 to 20, preferably 5 to 15, ring         atoms, which is mono- or polycyclic, and which is optionally         substituted by one or more identical or different substituents         having one of the meanings of L as defined above and below, and

R^(S1), R^(S2), R^(S3), R^(S4), R^(S5) and R^(S6) independently of each other denote H, CN or have one of the meanings of L as defined above and below.

Preferred compounds of formula XII are selected from the following subformulae:

wherein C_(n), k and l are as defined in formula XII, and

R^(S1), R^(S2), R^(S3), R^(S4) R^(S5) and R^(S6) independently of each other denote H or have one of the meanings of L as defined above and below.

Also preferably the polymer according to the present invention is blended with other type of n-type semiconductor such as graphene, a metal oxide, like for example, ZnOx, TiOx, ZTO, MoOx, NiOx, quantum dots, like for example, CdSe or CdS, or a conjugated polymer, like for example a polynaphthalenediimide or polyperylenediimide as described, for example, in WO2013142841 A1 to form the active layer in an OPV or OPD device.

The device preferably further comprises a first transparent or semi-transparent electrode on a transparent or semi-transparent substrate on one side of the active layer, and a second metallic or semi-transparent electrode on the other side of the active layer.

Preferably, the active layer according to the present invention is further blended with additional organic and inorganic compounds to enhance the device properties. For example, metal particles such as Au or Ag nanoparticles or Au or Ag nanoprism for enhancements in light harvesting due to near-field effects (i.e. plasmonic effect) as described, for example in Adv. Mater. 2013, 25 (17), 2385-2396 and Adv. Ener. Mater. 2014, 4, 1400206, a molecular dopant such as 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane for enhancement in photoconductivity as described, for example in Adv. Mater. 2013, 25(48), 7038-7044, or a stabilising agent consisting of a UV absorption agent and/or anti-radical agent and/or antioxidant agent such as 2-hydroxybenzophenone, 2-hydroxyphenylbenzotriazole, oxalic acid anilides, hydroxyphenyl triazines, merocyanines, hindered phenol, N-aryl-thiomorpholine, N-aryl-thiomorpholine-1-oxide, N-aryl-thiomorpholine-1,1-dioxide, N-aryl-thiazolidine, N-aryl-thiazolidine-1-oxide, N-aryl-thiazolidine-1,1-dioxide and 1,4-diazabicyclo[2.2.2]octane as described, for example, in WO2012095796 A1 and in WO2013021971 A1.

The device preferably may further comprise a UV to visible photo-conversion layer such as described, for example, in J. Mater. Chem. 2011, 21, 12331 or a NIR to visible or IR to NIR photo-conversion layer such as described, for example, in J. Appl. Phys. 2013, 113, 124509.

Further preferably the OPV or OPD device comprises, between the active layer and the first or second electrode, one or more additional buffer layers acting as hole transporting layer and/or electron blocking layer, which comprise a material such as metal oxides, like for example, ZTO, MoO_(x), NiO_(x), a doped conjugated polymer, like for example PEDOT:PSS and polypyrrole-polystyrene sulfonate (PPy:PSS), a conjugated polymer, like for example polytriarylamine (PTAA), an organic compound, like for example substituted triaryl amine derivatives such as N,N′-diphenyl-N,N′-bis(1-naphthyl)(1,1′-biphenyl)-4,4′diamine (NPB), N,N′-diphenyl-N,N′-(3-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD), graphene based materials, like for example, graphene oxide and graphene quantum dots or alternatively as hole blocking layer and/or electron transporting layer, which comprise a material such as metal oxide, like for example, ZnO_(x), TiO_(x), AZO (aluminium doped zinc oxide), a salt, like for example LiF, NaF, CsF, a conjugated polymer electrolyte, like for example poly[3-(6-trimethylammoniumhexyl)thiophene], poly(9,9-bis(2-ethylhexyl)-fluorene]-b-poly[3-(6-trimethylammoniumhexyl)thiophene], or poly[(9,9-bis(3′-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)], a polymer, like for example poly(ethyleneimine) or crosslinked N-containing compound derivatives or an organic compound, like for example tris(8-quinolinolato)-aluminium(III) (Alq₃), phenanthroline derivative or C₆₀ or C₇₀ based fullerenes, like for example, as described in Adv. Energy Mater. 2012, 2, 82-86.

In a blend or mixture of a polymer according to the present invention with a fullerene or modified fullerene, the ratio polymer:fullerene is preferably from 5:1 to 1:5 by weight, more preferably from 2:1 to 1:3 by weight, most preferably 1:1 to 1:2 by weight. A polymeric binder may also be included, from 5 to 95% by weight. Examples of binder include polystyrene (PS), polypropylene (PP) and polymethylmethacrylate (PMMA).

To produce thin layers in BHJ OPV devices the polymers, polymer blends or mixtures of the present invention may be deposited by any suitable method. Liquid coating of devices is more desirable than vacuum deposition techniques. Solution deposition methods are especially preferred. The formulations of the present invention enable the use of a number of liquid coating techniques. Preferred deposition techniques include, without limitation, dip coating, spin coating, ink jet printing, nozzle printing, letter-press printing, screen printing, gravure printing, doctor blade coating, roller printing, reverse-roller printing, offset lithography printing, dry offset lithography printing, flexographic printing, web printing, spray coating, curtain coating, brush coating, slot dye coating or pad printing. For the fabrication of OPV devices and modules area printing method compatible with flexible substrates are preferred, for example slot dye coating, spray coating and the like.

Suitable solutions or formulations containing a blend or mixture of a polymer according to the present invention with a fullerene or modified fullerene like PCBM are preferably prepared. In the preparation of such a formulation, suitable solvents are preferably selected to ensure full dissolution of both component, p-type and n-type and take into account the boundary conditions (for example rheological properties) introduced by the chosen printing method.

Organic solvent are generally used for this purpose. Typical solvents can be aromatic solvents, halogenated solvents or chlorinated solvents, including chlorinated aromatic solvents. Examples include, but are not limited to dichloromethane, trichloromethane, tetrachloromethane, chlorobenzene, o-dichlorobenzene, 1,2,4-trichlorobenzene, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,8-diiodooctane, 1-chloronaphthalene, 1,8-octane-dithiol, anisole, 2,5-di-methylanisole, 2,4-dimethylanisole, toluene, o-xylene, m-xylene, p-xylene, mixture of xylene o-, m-, and p-isomers, 1,2,4-trimethylbenzene, mesitylene, cyclohexane, 1-methylnaphthalene, 2-methylnaphthalene, 1,2-dimethylnaphthalene, tetraline, decaline, indane, 1-methyl-4-(1-methylethenyl)-cyclohexene (d-Limonene), 6,6-dimethyl-2-methylenebicyclo[3.1.1]heptanes (β-pinene), methyl benzoate, ethyl benzoate, nitrobenzene, benzaldehyde, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, morpholine, acetone, methylethylketone, ethyl acetate, n-butyl acetate, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide and/or mixtures thereof.

The OPV device can for example be of any type known from the literature (see e.g. Waldauf et al., Appl. Phys. Lett., 2006, 89, 233517).

A first preferred OPV device according to the invention comprises the following layers (in the sequence from bottom to top):

-   -   optionally a substrate,     -   a high work function electrode, preferably comprising a metal         oxide, like for example ITO and FTO, serving as anode,     -   an optional conducting polymer layer or hole transport layer,         preferably comprising an organic polymer or polymer blend, for         example PEDOT:PSS (poly(3,4-ethylenedioxythiophene):         poly(styrene-sulfonate), substituted triaryl amine derivatives,         for example, TBD         (N,N′-dyphenyl-N—N′-bis(3-methylphenyl)-1,1′biphenyl-4,4′-diamine)         or NBD         (N,N′-dyphenyl-N—N′-bis(1-napthylphenyl)-1,1′biphenyl-4,4′-diamine),     -   a layer, also referred to as “active layer”, comprising of at         least one p-type and at least one n-type organic semiconductor,         which can exist for example as a p-type/n-type bilayer or as         distinct p-type and n-type layers, or as blend or p-type and         n-type semiconductor, forming a BHJ,     -   optionally a layer having electron transport properties, for         example comprising LiF, TiO_(x), ZnO_(x), PFN, a         poly(ethyleneimine) or crosslinked nitrogen containing compound         derivatives or a phenanthroline derivatives     -   a low work function electrode, preferably comprising a metal         like for example aluminum, serving as cathode,     -   wherein at least one of the electrodes, preferably the anode, is         transparent to visible and/or NIR light, and     -   wherein at least one p-type semiconductor is a polymer according         to the present invention.

A second preferred OPV device according to the invention is an inverted OPV device and comprises the following layers (in the sequence from bottom to top):

-   -   optionally a substrate,     -   a high work function metal or metal oxide electrode, comprising         for example ITO and FTO, serving as cathode,     -   a layer having hole blocking properties, preferably comprising a         metal oxide like TiO_(x) or ZnO_(x), or comprising an organic         compound such as polymer like poly(ethyleneimine) or crosslinked         nitrogen containing compound derivatives or phenanthroline         derivatives,     -   an active layer comprising at least one p-type and at least one         n-type organic semiconductor, situated between the electrodes,         which can exist for example as a p-type/n-type bilayer or as         distinct p-type and n-type layers, or as blend or p-type and         n-type semiconductor, forming a BHJ,     -   an optional conducting polymer layer or hole transport layer,         preferably comprising an organic polymer or polymer blend, for         example of PEDOT:PSS or substituted triaryl amine derivatives,         for example, TBD or NBD,     -   an electrode comprising a high work function metal like for         example silver, serving as anode,     -   wherein at least one of the electrodes, preferably the cathode,         is transparent to visible and/or NIR light, and     -   wherein at least one p-type semiconductor is a polymer according         to the present invention.

In the OPV devices of the present invention the p-type and n-type semiconductor materials are preferably selected from the materials, like the polymer/fullerene systems or polymer/polymer systems, as described above

When the active layer is deposited on the substrate, it forms a BHJ that phase separates at nanoscale level. For discussion on nanoscale phase separation see Dennler et al, Proceedings of the IEEE, 2005, 93 (8), 1429 or Hoppe et al, Adv. Func. Mater, 2004, 14(10), 1005. An optional annealing step may be then necessary to optimize blend morphology and consequently OPV device performance.

Another method to optimize device performance is to prepare formulations for the fabrication of OPV(BHJ) devices that may include high boiling point additives to promote phase separation in the right way. 1,8-Octanedithiol, 1,8-diiodooctane, nitrobenzene, 1-chloronaphthalene, N,N-dimethylformamide, dimethylacetamide, dimethylsulfoxide and other additives have been used to obtain high-efficiency solar cells. Examples are disclosed in J. Peet, et al, Nat. Mater., 2007, 6, 497 or Fréchet et al. J. Am. Chem. Soc., 2010, 132, 7595-7597.

The polymers, polymer blends, mixtures and layers of the present invention are also suitable for use in an OTFT as the semiconducting channel. Accordingly, the invention also provides an OTFT comprising a gate electrode, an insulating (or gate insulator) layer, a source electrode, a drain electrode and an organic semiconducting channel connecting the source and drain electrodes, wherein the organic semiconducting channel comprises a polymer, polymer blend, mixture or organic semiconducting layer according to the present invention. Other features of the OTFT are well known to those skilled in the art.

OTFTs where an OSC material is arranged as a thin film between a gate dielectric and a drain and a source electrode, are generally known, and are described for example in U.S. Pat. Nos. 5,892,244, 5,998,804, 6,723,394 and in the references cited in the background section. Due to the advantages, like low cost production using the solubility properties of the compounds according to the invention and thus the processibility of large surfaces, preferred applications of these FETs are such as integrated circuitry, TFT displays and security applications.

The gate, source and drain electrodes and the insulating and semiconducting layer in the OTFT device may be arranged in any sequence, provided that the source and drain electrode are separated from the gate electrode by the insulating layer, the gate electrode and the semiconductor layer both contact the insulating layer, and the source electrode and the drain electrode both contact the semiconducting layer.

An OTFT device according to the present invention preferably comprises:

-   -   a source electrode,     -   a drain electrode,     -   a gate electrode,     -   a semiconducting layer,     -   one or more gate insulator layers,     -   optionally a substrate.

wherein the semiconductor layer preferably comprises a polymer, polymer blend or mixture according to the present invention.

The OTFT device can be a top gate device or a bottom gate device. Suitable structures and manufacturing methods of an OTFT device are known to the skilled in the art and are described in the literature, for example in US 2007/0102696 A1.

The gate insulator layer preferably comprises a fluoropolymer, like e.g. the commercially available Cytop 809M® or Cytop 107M® (from Asahi Glass). Preferably the gate insulator layer is deposited, e.g. by spin-coating, doctor blading, wire bar coating, spray or dip coating or other known methods, from a formulation comprising an insulator material and one or more solvents with one or more fluoro atoms (fluorosolvents), preferably a perfluorosolvent. A suitable perfluorosolvent is e.g. FC75® (available from Acros, catalogue number 12380). Other suitable fluoropolymers and fluorosolvents are known in prior art, like for example the perfluoropolymers Teflon AF® 1600 or 2400 (from DuPont) or Fluoropel® (from Cytonix) or the perfluorosolvent FC 43® (Acros, No. 12377). Especially preferred are organic dielectric materials having a low permittivity (or dielectric constant) from 1.0 to 5.0, very preferably from 1.8 to 4.0 (“low k materials”), as disclosed for example in US 2007/0102696 A1 or U.S. Pat. No. 7,095,044.

In security applications, OTFTs and other devices with semiconducting materials according to the present invention, like transistors or diodes, can be used for RFID tags or security markings to authenticate and prevent counterfeiting of documents of value like banknotes, credit cards or ID cards, national ID documents, licenses or any product with monetry value, like stamps, tickets, shares, cheques etc.

Alternatively, the polymers, polymer blends and mixtures according to the invention can be used in OLEDs, e.g. as the active display material in a flat panel display applications, or as backlight of a flat panel display like e.g. a liquid crystal display. Common OLEDs are realized using multilayer structures. An emission layer is generally sandwiched between one or more electron-transport and/or hole-transport layers. By applying an electric voltage electrons and holes as charge carriers move towards the emissive layer where their recombination leads to the excitation and hence luminescence of the lumophor units contained in the emission layer.

The polymers, polymer blends and mixtures according to the invention can be employed in one or more of a buffer layer, electron or hole transport layer, electron or hole blocking layer and emissive layer, corresponding to their electrical and/or optical properties. Furthermore their use within the emissive layer is especially advantageous, if the compounds, materials and films according to the invention show electroluminescent properties themselves or comprise electroluminescent groups or compounds. The selection, characterization as well as the processing of suitable monomeric, oligomeric and polymeric compounds or materials for the use in OLEDs is generally known by a person skilled in the art, see, e.g., Müller et al, Synth. Metals, 2000, 111-112, 31-34, Alcala, J. Appl. Phys., 2000, 88, 7124-7128 and the literature cited therein.

According to another use, the polymers, polymer blends and mixtures according to this invention, especially those showing photoluminescent properties, may be employed as materials of light sources, e.g. in display devices, as described in EP 0 889 350 A1 or by C. Weder et al., Science, 1998, 279, 835-837.

A further aspect of the invention relates to both the oxidised and reduced form of a polymer according to this invention. Either loss or gain of electrons results in formation of a highly delocalised ionic form, which is of high conductivity. This can occur on exposure to common dopants. Suitable dopants and methods of doping are known to those skilled in the art, e.g. from EP 0 528 662, U.S. Pat. No. 5,198,153 or WO 96/21659.

The doping process typically implies treatment of the semiconductor material with an oxidating or reducing agent in a redox reaction to form delocalised ionic centres in the material, with the corresponding counterions derived from the applied dopants. Suitable doping methods comprise for example exposure to a doping vapor in the atmospheric pressure or at a reduced pressure, electrochemical doping in a solution containing a dopant, bringing a dopant into contact with the semiconductor material to be thermally diffused, and ion-implantation of the dopant into the semiconductor material.

When electrons are used as carriers, suitable dopants are for example halogens (e.g., I₂, Cl₂, Br₂, ICl, ICl₃, IBr and IF), Lewis acids (e.g., PF₅, AsF₅, SbF₅, BF₃, BCl₃, SbCl₅, BBr₃ and SO₃), protonic acids, organic acids, or amino acids (e.g., HF, HCl, HNO₃, H₂SO₄, HClO₄, FSO₃H and ClSO₃H), transition metal compounds (e.g., FeCl₃, FeOCl, Fe(ClO₄)₃, Fe(4-CH₃C₆H₄SO₃)₃, TiCl₄, ZrCl₄, HfCl₄, NbF₅, NbCl₅, TaCl₅, MoF₅, MoCl₅, WF₅, WCl₆, UF₆ and LnCl₃ (wherein Ln is a lanthanoid), anions (e.g., Cl⁻, Br⁻, I⁻, I₃ ⁻, HSO₄ ⁻, SO₄ ²⁻, NO₃ ⁻, ClO₄ ⁻, BF₄ ⁻, PF₆ ⁻, AsF₆ ⁻, SbF₆ ⁻, Fe(CN)₆ ³⁻, and anions of various sulfonic acids, such as aryl-SO₃ ⁻). When holes are used as carriers, examples of dopants are cations (e.g., H⁺, Li⁺, Na⁺, K⁺, Rb⁺ and Cs⁺), alkali metals (e.g., Li, Na, K, Rb, and Cs), alkaline-earth metals (e.g., Ca, Sr, and Ba), O₂, XeOF₄, (NO₂ ⁺) (SbF₆ ⁻), (NO₂ ⁺) (SbCl₆ ⁻), (NO₂ ⁺) (BF₄ ⁻), AgClO₄, H₂IrCl₆, La(NO₃)₃.6H₂O, FSO₂OOSO₂F, Eu, acetylcholine, R₄N⁺, (R is an alkyl group), R₄P⁺ (R is an alkyl group), R₆As⁺ (R is an alkyl group), and R₃S⁺ (R is an alkyl group).

The conducting form of a polymer of the present invention can be used as an organic “metal” in applications including, but not limited to, charge injection layers and ITO planarising layers in OLED applications, films for flat panel displays and touch screens, antistatic films, printed conductive substrates, patterns or tracts in electronic applications such as printed circuit boards and condensers.

The polymers, polymer blends and mixtures according to the present invention may also be suitable for use in organic plasmon-emitting diodes (OPEDs), as described for example in Koller et al., Nat. Photonics, 2008, 2, 684.

According to another use, the polymers according to the present invention can be used alone or together with other materials in or as alignment layers in LCD or OLED devices, as described for example in US 2003/0021913. The use of charge transport polymers according to the present invention can increase the electrical conductivity of the alignment layer. When used in an LCD, this increased electrical conductivity can reduce adverse residual dc effects in the switchable LCD cell and suppress image sticking or, for example in ferroelectric LCDs, reduce the residual charge produced by the switching of the spontaneous polarisation charge of the ferroelectric LCs. When used in an OLED device comprising a light emitting material provided onto the alignment layer, this increased electrical conductivity can enhance the electroluminescence of the light emitting material. The polymers according to the present invention having mesogenic or liquid crystalline properties can form oriented anisotropic films as described above, which are especially useful as alignment layers to induce or enhance alignment in a liquid crystal medium provided onto said anisotropic film. The polymers according to the present invention may also be combined with photoisomerisable compounds and/or chromophores for use in or as photoalignment layers, as described in US 2003/0021913 A1.

According to another use the polymers, polymer blends and mixtures according to the present invention, especially their water-soluble derivatives (for example with polar or ionic side groups) or ionically doped forms, can be employed as chemical sensors or materials for detecting and discriminating DNA sequences. Such uses are described for example in L. Chen, D. W. McBranch, H. Wang, R. Helgeson, F. Wudl and D. G. Whitten, Proc. Natl. Acad. Sci. U.S.A., 1999, 96, 12287; D. Wang, X. Gong, P. S. Heeger, F. Rininsland, G. C. Bazan and A. J. Heeger, Proc. Natl. Acad. Sci. U.S.A., 2002, 99, 49; N. DiCesare, M. R. Pinot, K. S. Schanze and J. R. Lakowicz, Langmuir, 2002, 18, 7785; D. T. McQuade, A. E. Pullen, T. M. Swager, Chem. Rev., 2000, 100, 2537.

Unless the context clearly indicates otherwise, as used herein plural forms of the terms herein are to be construed as including the singular form and vice versa.

Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of the words, for example “comprising” and “comprises”, mean “including but not limited to”, and are not intended to (and do not) exclude other components.

It will be appreciated that variations to the foregoing embodiments of the invention can be made while still falling within the scope of the invention. Each feature disclosed in this specification, unless stated otherwise, may be replaced by alternative features serving the same, equivalent or similar purpose. Thus, unless stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

All of the features disclosed in this specification may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. In particular, the preferred features of the invention are applicable to all aspects of the invention and may be used in any combination. Likewise, features described in non-essential combinations may be used separately (not in combination).

Above and below, unless stated otherwise percentages are percent by weight and temperatures are given in degrees Celsius. The values of the dielectric constant ε (“permittivity”) refer to values taken at 20° C. and 1,000 Hz.

The invention will now be described in more detail by reference to the following examples, which are illustrative only and do not limit the scope of the invention.

Example 1 3,6-Dibromo-4,5-dichlorophthalic Anhydride (1.1)

4,5-Dichlorophthalic anhydride (11.43 g, 51.60 mmol) was added into stirred fuming sulfuric acid (100 cm³) and the mixture was heated to 80° C. and stirred for 30 minutes to afford a clear solution. Dibromoisocyanuric acid (16.78 g, 56.74 mmol) was added in small portions under the heating and stirring conditions and the mixture was stirred at 80° C. for 20 hours after the addition to yield an orange suspension. The suspension was cooled to 23° C. then poured onto crushed ice (ca 1 kg). The solid was collected by filtration and washed with water three times then with methanol twice.

The solid was boiled in water (600 cm³) then cooled, suction filtered, washed with water then air-dried. The boiling, filtering and washing process was repeated three times and the solid was finally washed with methanol and dried to yield 3,6-dibromo-4,5-dichlorophthalimide (1.1) (16.14 g, 83%) as a white solid ¹³C NMR (101 MHz, DMSO-d₆) δ 165.70, 135.70, 135.11, 119.97, 39.50. MS (EI) m/z 374.

3,6-Dibromo-4,5-dichloro-N-hexadecylphthalimide (1.2)

A round bottom flask was charged with 4,7-dibromo-5,6-dichlorophthalic anhydride (1.1) (3.70 g, 9.87 mmol), hexadecylamine (2.62 g, 10.86 mmol) and propionic acid (40 cm³). The mixture was stirred at 140° C. (external) for 3 hours and then cooled to 23° C. where a precipitate occurred. Ethanol (50 cm³) was added and the solid collected by filtration, washed with ethanol then methanol to give 3,6-dibromo-4,5-dichloro-N-hexadecylphthalimide (1.2) (5.10 g, 86%) as a white crystalline solid. MS (EI) m/z 597. ¹H NMR (400 MHz, CDCl₃) δ 3.69 (t, J=7.3 Hz, 2H), 1.66 (m, J=7.2 Hz, 2H), 1.31 (s, 6H), 1.24 (s, 20H), 0.87 (t, J=6.8 Hz, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 163.79, 141.44, 129.95, 119.22, 39.11, 31.92, 29.68, 29.67, 29.64, 29.60, 29.54, 29.41, 29.35, 29.09, 28.20, 26.78, 22.68, 14.11.

4,5-Dichloro-3,6-bis(thieno[3,2-b]thiophen-2-yl)-N-hexadecylphthalimide (1.3)

A mixture of 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)thieno[3,2-b]thiophene (1.757 g, 6.600 mmol), 3,6-dibromo-4,5-dichloro-N-hexadecylphthalimide (1.2) (1.80 g, 3.00 mmol) and sodium carbonate 2 M aqueous solution (6.6 cm³, 13.20 mmol) with toluene (40 cm³) and THF (10.0 cm³) was degassed by bubbling nitrogen for 20 minutes. The mixture of tris(dibenzylideneacetone)dipalladium(0) (55 mg, 0.060 mmol) and tri-o-tolylphosphine (73 mg, 0.24 mmol) was added in one portion and the mixture was degassed with nitrogen for an additional 10 minutes. The mixture was heated at reflux for 16 hours. The mixture was cooled to 23° C. and the solvents were removed by rotary evaporation in vacuo. The residue was triturated with methanol then suction filtered and the solid washed with methanol, water and methanol. The crude was purified by column chromatogaphy (1:1 v/v dichloromethane-petroleum ether (40-60)) to give 4,5-dichloro-3,6-bis(thieno[3,2-b]thiophen-2-yl)-N-hexadecylphthalimide (1.3) (1.01 g, 47%) as a bright yellow microcrystalline solid. ¹HNMR (400 MHz, DCM-d₂) δ 7.50 (d, J=5.3 Hz, 2H), 7.36 (dd, J=5.3, 0.7 Hz, 2H), 7.32 (d, J=0.7 Hz, 2H), 3.51 (q, J=8.0 Hz, 2H), 1.53 (s, 2H), 1.34-1.13 (m, 26H), 0.86 (t, J=8.0 Hz, 3H). ¹³C NMR (101 MHz, CD₂Cl₂) δ 165.32, 141.22, 141.05, 139.11, 134.70, 133.31, 130.00, 128.59, 122.01, 119.82, 38.84, 32.27, 30.03, 30.00, 29.96, 29.89, 29.77, 29.70, 29.43, 28.52, 27.15, 23.04, 14.24.

3,6-Bis(5-bromothieno[3,2-b]thiophen-2-yl)-4,5-dichloro-N-hexadecylphthalimide (1.4)

To a solution of 4,5-dichloro-3,6-bis(thieno[3,2-b]thiophen-2-yl)-N-hexadecylphthalimide (1.3) (4.75 g, 6.63 mmol) in anhydrous tetrahydrofuran (130 cm³) was added N-bromosuccinimide (3.57 g, 19.88 mmol) in one portion. The solution was heated at reflux for 4 hours. Further N-bromosuccinimide (1.2 g) was added and the mixture heated at reflux for a further 2 hours. The mixture was concentrated to dryness in vacuo and the residue was triturated in ethanol (100 cm³). The solid was collected by filtration, washed with ethanol 2 times and acetone 3 times followed by recrystallisation from cyclohexane to give 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-4,5-dichloro-N-hexadecylphthalimide (1.4) (4.81 g, 83%) as a green-yellow solid. ¹H NMR (400 MHz, CD₂Cl₂) δ 7.38 (s, 2H), 7.23 (s, 2H), 3.50 (t, J=7.3 Hz, 2H), 1.52 (m, 2H), 1.34-1.14 (m, 26H), 0.87 (t, J=7.0 Hz, 3H). ¹³C NMR (101 MHz, CD₂Cl₂) δ 165.27, 141.08, 140.09, 139.30, 134.21, 132.97, 130.06, 122.66, 121.73, 114.98, 38.93, 32.33, 30.09, 30.06, 30.02, 29.94, 29.82, 29.76, 29.47, 28.57, 27.20, 23.10, 14.30.

3,6-Bis(5-bromothieno[3,2-b]thiophen-2-yl)-N-hexadecyl(2-dicyanomethylene-1,3-dithiolo[4,5-d])phthalimide (1)

To a solution of 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-4,5-dichloro-N-hexadecylphthalimide (1.4) (2.62 g, 3.00 mmol) in anhydrous N,N-dimethylformamide (80 cm³) at 50° C. was added di(sodiummercapto)methylenemalononitrile (0.838 g, 4.50 mmol) in one portion. The solution was stirred at 50° C. for 8 hours and the solvent was removed in vacuo. The residue was triturated with methanol and the solid was collected by suction filtration. The solid was purified by column chromatography (3:1 dichloromethane-cyclohexane) followed by recrystallization from chloroform-octane to give 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-N-hexadecyl(2-dicyanomethylene-1,3-dithiolo[4,5-d])phthalimide (1) (1.95 g, 68%) as a yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 7.41 (s, 2H), 7.36 (s, 2H), 3.59 (t, J=7.3 Hz, 2H), 1.59 (m, 2H), 1.36-1.15 (m, 26H), 0.88 (t, J=7.0 Hz, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 175.85, 164.77, 144.38, 140.41, 139.33, 132.67, 129.41, 127.79, 122.08, 121.89, 116.74, 111.92, 67.74, 38.81, 31.91, 29.68, 29.66, 29.63, 29.58, 29.50, 29.40, 29.34, 29.04, 28.24, 26.84, 22.68, 14.12.

Example 2 3,6-Bis(5-bromothieno[3,2-b]thiophen-2-yl)-N-hexadecyl(2-thioxo-1,3-dithiolo[4,5-d])phthalimide (2)

To a suspension of anhydrous sodium sulfide (0.351 g, 4.50 mmol) in anhydrous N,N-dimethylformamide (50 cm³) was added carbon disulfide (0.5 cm³, 8.27 mmol) in one portion. The mixture was stirred at 23° C. for 2 hours and 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-4,5-dichloro-N-hexadecylphthalimide (1.4) (2.62 g, 3.00 mmol) was added. The mixture was stirred at 50° C. for 2 hours and at 100° C. for 1 hour. Methanol (50 cm³) was added under stirring and the mixture was allowed to cool to 23° C. The solid was collected by suction filtration, washed with methanol, recrystallised from chloroform-ethanol then passed through a silica plug (chloroform). The solid was finally recrystallised from chloroform-cyclohexane to give 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-N-hexadecyl(2-thioxo-1,3-dithiolo[4,5-d])phthalimide (1.92 g, 70%) as an orange solid. ¹H NMR (400 MHz, CDCl₃) δ 7.38 (s, 2H), 7.33 (s, 2H), 3.58 (t, J=7.4 Hz, 2H), 1.60 (m, 2H), 1.23 (m, 26 H), 0.87 (t, J=7.4 Hz, 3H). ¹³C NMR (101 MHz, CDCl₃) δ 208.54, 165.42, 149.46, 140.09, 139.12, 133.62, 128.50, 126.00, 122.08, 121.57, 116.00, 38.65, 31.92, 29.68, 29.67, 29.64, 29.59, 29.52, 29.42, 29.35, 29.07, 28.28, 26.90, 26.87, 22.69, 14.13.

Example 3—Polymer 1 (P1)

A flask was charged with 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-N-hexadecyl(2-dicyanomethylene-1,3-dithiolo[4,5-d])phthalimide (1) (TT2-DCMDT-PI)(236.0 mg, 0.250 mmol), 2,8-bis(trimethylstannyl)-[6,6,12,12-tetrakis(4-hexadecylphenyl)-6,12-dihydrodithieno[2,3-d:2′, 3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (IDTT-diTin) (476.6 mg, 0.250 mmol), anhydrous toluene (5.0 cm³) and anhydrous N,N-dimethylformamide (1.0 cm³). The mixture was degassed by bubbling nitrogen for 30 minutes and tris(dibenzylideneacetone)dipalladium(0) (7.0 mg, 0.010 mmol) and tri-o-tolylphosphine (12.2 mg, 0.040 mmol) were added. The mixture was degassed for an additional 15 minutes, then vigorously stirred at 120° C. under nitrogen for 5 minutes. Iodobenzene (0.20 cm³, 1.8 mmol) and toluene (5 cm³) were added and the mixture was stirred for another 60 minutes at 120° C. The solution was precipitated into stirred acetone (100 cm³) and the mixture was stirred at 20° C. for 30 minutes. The solid was collected by suction filtration, washed with acetone, then Soxhlet extracted with acetone, petroleum ether (40-60), petroleum ether (80-100) sequentially and finally dissolved in chloroform. The chloroform solution was concentrated and precipitated into acetone. The solid was collected by suction filtration to give polymer 1 (0.52 g, 88%) as a deep red solid. GPC (chlorobenzene, 50° C.): Mn=94,000 Kg/mol, Mw=352,000 kg/mol, PDI=3.73.

Example 4—Polymer 2 (P2)

A 25 cm³ round-bottom flask was charged 9,10-dioctyl-2,7-phenanthrylene-bis(1,3,2-dioxaborolane) (122.3 mg, 0.225 mmol), 3,6-bis(5-bromothieno[3,2-b]thiophen-2-yl)-N-hexadecyl(2-dicyanomethylene-1,3-dithiolo[4,5-d])phthalimide (1) (TT2-DCMDT-PI)(212.9 mg, 0.225 mmol) and potassium phosphate monohydrate (208 mg, 0.902 mmol). To this mixture were added 1,4-dioxane (2 cm³) and water (HPLC grade, 2 cm³). The thick yellow suspension was degassed by bubbling nitrogen gas for 40 minutes. In the meantime, a stock solution of catalyst prepared from tris(dibenzylideneacetone)dipalladium(0) (2.6 mg, 0.003 mmol) and tri-o-tolylphosphine (5.5 mg, 0.018 mmol) in 1,4-dioxane (0.4 cm³) was degassed and then added through a syringe. The mixture was further degassed for 10 minutes. The flask was lowered into a preheated oil bath and vigorously stirred for 20 hours at 120° C. to yield a red suspension. The suspension was cooled briefly then precipitated into methanol (50 cm³). The red solid was collected by suction filtration, washed with methanol, water, acetone sequentially and finally air-dried (0.26 g, 97%). The polymer P2 solid was very insoluble in most organic solvents. The soluble fraction from chlorobenzene gave molecular weights of M_(n)=28,600 kg/mol and M_(w)=32,500 kg/mol. PDI=1.14.

Use Example A

Field-Effect Transistor Fabrication and Measurements: General Procedure

Top-gate thin-film organic field-effect transistors (OFETs) were fabricated on glass substrates with vacuum evaporated Au source-drain electrodes. A 7 mg/cm³ solution of the organic semiconductor in dichlorobenzene was spin-coated on top (an optional annealing of the film is carried out at 100° C., 150° C. or 200° C. for between 1 and 5 minutes) followed by a spin-coated fluoropolymer dielectric material (Lisicon® D139 from Merck, Germany). Finally a vacuum evaporated Au gate electrode was deposited. The electrical characterization of the transistor devices was carried out in ambient air atmosphere using computer controlled Agilent 4155C Semiconductor Parameter Analyser. Charge carrier mobility in the saturation regime (μ_(sat)) was calculated for the compound. Field-effect mobility was calculated in the saturation regime (V_(d)>(V_(g)−V₀)) using equation (1):

$\begin{matrix} {\left( \frac{{dI}_{d}^{sat}}{{dV}_{g}} \right)_{V_{d}} = {\frac{{WC}_{i}}{L}{\mu^{sat}\left( {V_{g} - V_{0}} \right)}}} & (1) \end{matrix}$

where W is the channel width, L the channel length, C_(i) the capacitance of insulating layer, V_(g) the gate voltage, V₀ the turn-on voltage, and μ_(sat) is the charge carrier mobility in the saturation regime. Turn-on voltage (V₀) was determined as the onset of source-drain current.

The μ_(sat) for polymer 1 was shown to be 5×10⁻⁴ cm²/Vs with I_(on)/I_(off) of 10⁴ 

The invention claimed is:
 1. A compound comprising one or more divalent heteroarylene units of formula I

wherein X¹, X² are independently of each other and on each occurrence identically or differently selected from O or S, Y is independently of each other and on each occurrence identically or differently selected from O, S or CU¹U², U¹, U² are an electron withdrawing group selected from CN, C(═O)R or C(═O)OR, or U¹ and U² together form a carbocyclic, heterocyclic, aromatic or heteroaromatic ring having 4, 6-11, 13-15 ring atoms that is optionally substituted by one or more groups L, R¹ is independently of each other and on each occurrence identically or differently selected from H or straight-chain, branched or cyclic alkyl with 1 to 30 C atoms, in which one or more CH₂ groups are optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —C(═O)—O—, —O—C(═O)—, —NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CR⁰═CR⁰⁰—, —CY¹═CY²— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another, and in which one or more H atoms are optionally replaced by F, Cl, Br, I or CN, and in which one or more CH₂ or CH₃ groups are optionally replaced by a cationic or anionic group, or aryl, heteroaryl, arylalkyl, heteroarylalkyl, aryloxy or heteroaryloxy, wherein each of the aforementioned cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, and is unsubstituted or substituted by one or more identical or different groups L, R is independently of each other and on each occurrence identically or differently selected from straight-chain, branched or cyclic alkyl with 1 to 30 C atoms, in which one or more CH₂ groups are optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —C(═O)—O—, —O—C(═O)—, —NR⁰, —SiR⁰R⁰⁰, —CF₂—, —CR⁰═CR⁰⁰—, —CY¹═CY²— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another, and in which one or more H atoms are optionally replaced by F, Cl, Br, I or CN, and in which one or more CH₂ or CH₃ groups are optionally replaced by a cationic or anionic group, or aryl, heteroaryl, arylalkyl or heteroarylalkyl, wherein each of the aforementioned cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, and is unsubstituted or substituted by one or more identical or different groups L, L is independently of each other and on each occurrence identically or differently selected from F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R⁰, OR⁰, SR⁰, —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰, —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃R⁰, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, Y¹, Y² are independently of each other and on each occurrence identically or differently selected from H, F, C1 or CN, X⁰ is halogen, R⁰, R⁰⁰ are independently of each other and on each occurrence identically or differently selected from H or straight-chain or branched alkyl with 1 to 20 C atoms that is optionally fluorinated, with the proviso that, if X¹, X² and Y are O, then the divalent heteroarylene unit of formula I is bonded via the 1- or 4-position of the benzene ring to at least one group that is different from H, wherein the compound is a conjugated polymer comprising one or more repeating units of formula II1 or II2, and optionally one or more repeating units of formula II3: —(Ar¹)_(a)—U—(Ar²)_(b)—(Ar³)_(c)—(Ar⁴)_(d)—  II1 —(Ar¹)_(a)—(Ar²)_(b)—U—(Ar³)_(c)—(Ar⁴)_(d)—  II2 —(Ar¹)_(a)—(Ar²)_(b)—(Ar³)_(c)—(Ar⁴)_(d)—  II3 wherein U is a unit of formula I, Ar¹⁻⁴ are independently of each other and on each occurrence identically or differently selected from arylene, heteroarylene that has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, is unsubstituted or substituted by one or more identical or different groups L, provided that the Ar¹⁻⁴ groups are different from the groups of formula I, a, b, c, d are 0 or 1, wherein in formula II3 a+b+c+d≥1, or wherein the compound is a monomer of formula V1 or V2 R⁷—(Ar¹)_(a)—U—(Ar²)_(b)—(Ar³)_(c)—(Ar⁴)_(d)—R⁸  V1 R⁷—(Ar¹)_(a)—(Ar²)_(b)—U—(Ar³)_(c)—(Ar⁴)_(d)—R⁸  V2 wherein R⁷ and R⁸ are independently of each other selected from the group consisting of H, Cl, Br, I, O-tosylate, O-triflate, O-mesylate, O-nonaflate, —SiMe₃, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂, —CZ³═C(Z³)₂, —C≡CH, —C≡CSi(Z¹)₃, —ZnX⁰, MgX⁰ and —Sn(Z⁴)₃, wherein X⁰ is halogen, Z¹⁻⁴ are selected from the group consisting of C₁₋₁₀ alkyl and C₆₋₁₂ aryl, each being optionally substituted, and two groups Z² may also form a cycloboronate group having 2 to 20 C atoms together with the B- and O-atoms, and wherein at least one of R⁷ and R⁸ is different from H, or wherein the compound is selected of formula VI

wherein Ar²¹⁻²⁸ are one of the meanings given for Art, or a unit of formula I, or —CY¹═CY²—, R^(1t), R^(2t) are H, F, Cl, Br, —CF₃, R*, —CF₂—R*, —O—R*, —S—R*, —SO₂—R*, —SO₃—R*, —C(═O)—R*, —C(═S)—R*, —C(═O)—CF₂—R*, —C(═O)—OR*, —C(═S)—OR*, —O—C(═O)—R*, —O—C(═S)—R*, —C(═O)—SR*, —S—C(═O)—R*, —C(═O)NR*R**, —NR*—C(═O)—R*, —NHR*, —NR*R**, —CR*═CR*R**, —C≡C—R*, —C≡C—SiR*R**R***, —SiR*R**R***, —CH═C(CN)—C(═O)—OR*, —CH═C(CO—OR*)₂, —CH═C(CO—NR*R**)₂, —CH═C(CN)(Ar⁹),

Ar⁹, Ar¹⁰ are aryl or heteroaryl, each having from 4 to 30 ring atoms, optionally containing fused rings and being unsubstituted or substituted with one or more groups L, R*, R**, R*** are alkyl with 1 to 20 C atoms which is straight-chain, branched or cyclic, and is unsubstituted, or substituted with one or more F or Cl atoms or CN groups, or perfluorinated, and in which one or more C atoms are optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —SiR⁰R⁰⁰—, —NR⁰R⁰⁰—, —CHR⁰═CR⁰⁰— or —C≡C— such that O— and/or S— atoms are not directly linked to each other, a-h are 0 or 1, m is 1, 2 or 3, r is 0, 1, 2, 3 or 4, with the proviso that if a+b+c+d+e+f+g+h=0 and X¹, X² and Y are O, then at least one of R^(1t) and R^(2t) is different from H.
 2. The compound according to claim 1, wherein R¹ and R denote alkyl, alkoxy or thiaalkyl, all of which are straight-chain or branched, have 1 to 25 C atoms, and are optionally fluorinated.
 3. The compound according to claim 1, which comprises one or more repeating units selected from the following formulae:

wherein X has on each occurrence identically or differently one of the meanings of X¹ and X², t is 1, 2, 3 or 4, and R², R³ and R⁴ have independently of each other and on each occurrence identically or differently one of the meanings given of L.
 4. The compound according to claim 1, which is a conjugated polymer of formula III: *

(A)_(x)-(B)_(y)

_(n)*  III wherein A is a unit of formula I, B is a unit of formula I, which is different from A, x is >0 and ≤1, y is ≥0 and <1, x+y is 1, and n is an integer ≥5.
 5. The compound according to claim 1, which is a conjugated polymer selected from the following formulae

wherein X^(1a) has one of the meanings given for X¹, X^(2a) has one of the meanings given for X¹, Y^(a) has one of the meanings given for Y, R^(1a) has one of the meanings given for R¹, Ar²⁻⁴ are arylene or heteroarylene that has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, is unsubstituted or substituted by one or more identical or different groups L, provided that the Ar²⁻⁴ groups are different from the groups of formula I, a, b, c, d are 0 or 1, x is >0 and ≤1, y is ≥0 and <1, x+y is 1, n is an integer ≥5, and in formula III3 and III5 at least one of X¹, X², Y and R¹ is different from its corresponding radical X^(1a), X^(2a), Y^(a) and R^(1a), respectively.
 6. The compound according to claim 1, wherein one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene selected from the group consisting of the following formulae

wherein R¹¹, R¹², R¹³, R¹⁴ independently of each other denote H, F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R⁰, OR⁰, SR⁰, —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰, —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃R⁰, —SO₂RO, —OH, —NO₂, —CF₃, —SF₅, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, X⁰ is halogen, and R⁰, R⁰⁰ are independently of each other and on each occurrence identically or differently selected from H or straight-chain or branched alkyl with 1 to 20 C atoms that is optionally fluorinated.
 7. The compound according to claim 3, wherein one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene selected from the group consisting of the following formulae

wherein R¹¹, R¹², R¹³, R¹⁴ independently of each other denote H, F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R⁰, OR⁰, SR⁰, —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰, —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃RO, —SO₂RO, —OH, —NO₂, —CF₃, —SF₅, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, X⁰ is halogen, and R⁰, R⁰⁰ are independently of each other and on each occurrence identically or differently selected from H or straight-chain or branched alkyl with 1 to 20 C atoms that is optionally fluorinated.
 8. The compound according to claim 1, wherein one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene selected from the group consisting of the following formulae

wherein R¹¹ and R¹² independently of each other denote H, F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R⁰, OR⁰, SR⁰, —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰, —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃R⁰, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, X⁰ is halogen, and R⁰, R⁰⁰ are independently of each other and on each occurrence identically or differently selected from H or straight-chain or branched alkyl with 1 to 20 C atoms that is optionally fluorinated.
 9. The compound according to claim 1, which is a conjugated polymer selected from the following formulae

wherein 0<x≤1, 0≤y<1, 0<z<1, x+y+z=1, X has on each occurrence identically or differently one of the meanings of X¹ and X², t is 1, 2, 3 or 4, n is an integer ≥5, and R², R³ and R⁴ have independently of each other and on each occurrence identically or differently one of the meanings given for L.
 10. The compound according to claim 1, which is a conjugated polymer of formula IV R⁵-chain-R⁶  IV wherein “chain” denotes a polymer chain selected from formulae III: *

(A)_(x)-(B)_(y)

_(n)*  III wherein A is a unit of formula I, B is a unit of formula I, which is different from A, x is >0 and ≤1, y is ≥0 and <1, x+y is 1, and n is an integer ≥5, and R⁵ and R⁶ have independently of each other one of the meanings of R¹ or L, or denote, independently of each other, H, F, Br, Cl, I, —CH₂Cl, —CHO, —CR′═CR″₂, —SiR′R″R′″, —SiR′X′X″, —SiR′R″X′, —SnR′R″R′″, —BR′R″, —B(OR′)(OR″), —B(OH)₂, —O—SO₂—R′, —C≡CH, —C≡C—SiR′₃, —ZnX′ or an endcap group, X′ and X″ denote halogen, R′, R″ and R′″ have independently of each other one of the meanings of R⁰, and two of R′, R″ and R′″ may also form a cyclosilyl, cyclostannyl, cycloborane or cycloboronate group with 2 to 20 C atoms together with the respective hetero atom to which they are attached.
 11. The compound of claim 1, which is selected from the following formulae R⁷—Ar¹—U—Ar²—R⁸  V1a R⁷—U—R⁸  V1b R⁷—Ar¹—U—R⁸  V1c R⁷—U—Ar²—R⁸  V1d.
 12. The compound of claim 1, which is selected of formula V3 R⁷—U*—R⁸  V3 wherein U* is a unit selected from formulae R1-R11:

wherein R¹ is independently of each other and on each occurrence identically or differently selected from H or straight-chain, branched or cyclic alkyl with 1 to 30 C atoms, in which one or more CH₂ groups are optionally replaced by —O—, —S—, —C(═O)—, —C(═S)—, —C(═O)—O—, —O—C(═O)—, —NR⁰—, —SiR⁰R⁰⁰—, —CF₂—, —CR⁰═CR⁰⁰—, —CY¹═CY²— or —C≡C— in such a manner that O and/or S atoms are not linked directly to one another, and in which one or more H atoms are optionally replaced by F, Cl, Br, I or CN, and in which one or more CH₂ or CH₃ groups are optionally replaced by a cationic or anionic group, or aryl, heteroaryl, arylalkyl, heteroarylalkyl, aryloxy or heteroaryloxy, wherein each of the aforementioned cyclic groups has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, and is unsubstituted or substituted by one or more identical or different groups L, X is O or S, Y is O, S or CU¹U², U¹, U² are an electron withdrawing group selected from CN, C(═O)R or C(═O)OR, or U¹ and U² together form a carbocyclic, heterocyclic, aromatic or heteroaromatic ring having 4 to 15 ring atoms that is optionally substituted by one or more groups L, L is independently of each other and on each occurrence identically or differently selected from F, Cl, —CN, —NC, —NCO, —NCS, —OCN, —SCN, R⁰, OR⁰, SR⁰, —C(═O)X⁰, —C(═O)R⁰, —C(═O)—OR⁰, —O—C(═O)—R⁰, —NH₂, —NHR⁰, —NR⁰R⁰⁰, —C(═O)NHR⁰, —C(═O)NR⁰R⁰⁰, —SO₃R⁰, —SO₂R⁰, —OH, —NO₂, —CF₃, —SF₅, or optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 20 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, X⁰ is halogen, R⁰, R⁰⁰ are independently of each other and on each occurrence identically or differently selected from H or straight-chain or branched alkyl with 1 to 20 C atoms that is optionally fluorinated, t is 1, 2, 3 or 4, R², R³ and R⁴ have independently of each other and on each occurrence identically or differently one of the meanings given of L.
 13. The compound according to claim 1, wherein: a) one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene from the group consisting of the following formulae

wherein R¹¹, R¹², R¹³, R¹⁴ independently of each other denote H or have one of the meanings of L, and/or b) one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene selected from the group consisting of the formulae

wherein R¹¹, R¹², R¹³, R¹⁴ independently of each other denote H or have one of the meanings of L, and c) one or more of Ar¹, Ar², Ar³ and Ar⁴ denote arylene or heteroarylene selected from the group consisting of the formulae

wherein R¹¹ and R¹² independently of each other denote H or have one of the meanings of L.
 14. The compound of claim 1, wherein Ar²¹⁻²⁸ are selected from the following groups a) the group consisting of the formulae D1, D7, D10, D11, D19, D22, D29, D30, D35, D36, D44, D106, D111, D140 and D140:

wherein R¹¹, R¹², R¹³, R¹⁴ independently of each other denote H or have one of the meanings of L, b) the group consisting of the formulae A1, A6, A7, A15, A16, A20, A74, A88, A92 and A98

wherein R¹¹, R¹², R¹³, R¹⁴ independently of each other denote H or have one of the meanings of L, and c) the group consisting of the formulae Sp1, Sp6 and Sp10:

wherein R¹¹ and R¹² independently of each other denote H or have one of the meanings of L.
 15. The compound of claim 1, which is selected of formula VI1 R^(1t)—U*—R^(2t)  VI1 wherein U* is a unit selected from formulae R¹-R¹¹:

wherein X has on each occurrence identically or differently one of the meanings of X¹ and X², t is 1, 2, 3 or 4, and R², R³ and R⁴ have independently of each other and on each occurrence identically or differently one of the meanings given for L.
 16. A mixture comprising one or more compounds according to claim 1 and one or more additional compounds having one or more of semiconducting, charge transport, hole or electron transport, hole or electron blocking, electrically conducting, photoconducting or light emitting properties.
 17. A mixture comprising one or more compounds according to claim 1, and one or more n-type organic semiconductors.
 18. The mixture of claim 17, wherein the n-type organic semiconductors are selected from fullerenes or substituted fullerenes.
 19. A formulation comprising one or more compounds according to claim 1 and further comprising one or more organic solvents.
 20. A semiconducting, charge transport, electrically conducting, photoconducting or light emitting material comprising a compound according to claim
 1. 21. An optical, electrooptical, electronic, electroluminescent or photoluminescent device, or a component thereof, or an assembly comprising such a device or component, which comprises the compound according to claim
 1. 22. The optical, electrooptical, electronic, electroluminescent or photoluminescent device of claim 21, which is selected from organic thin film transistors (OTFT), organic thin film transistors (OTFT), organic light emitting diodes (OLED), organic light emitting transistors (OLET), organic photovoltaic devices (OPV), organic photodetectors (OPD), organic solar cells, dye-sensitized solar cells (DSSC), perovskite-based solar cells, laser diodes, Schottky diodes, photoconductors and photodetectors.
 23. The component of claim 21, which is selected from charge injection layers, charge transport layers, interlayers, planarising layers, antistatic films, polymer electrolyte membranes (PEM), conducting substrates and conducting patterns.
 24. The assembly of claim 21, which is selected from integrated circuits (IC), radio frequency identification (RFID) tags or security markings or security devices containing them, flat panel displays or backlights thereof, electrophotographic devices, electrophotographic recording devices, organic memory devices, sensor devices, biosensors and biochips.
 25. A bulk heterojunction comprising a mixture according to claim
 16. 26. A bulk heterojunction (BHJ) OPV device or inverted BHJ OPV device, comprising a bulk heterojunction of claim
 25. 27. The compound according to claim 1, wherein the conjugated polymer is prepared by coupling one or more monomers selected from the monomers of formula V1 or V2: R⁷—(Ar¹)a—U—(Ar²)b—(Ar³)c—(Ar⁴)d—R⁸  V1 R⁷—(Ar¹)a—(Ar²)b—U—(Ar³)c—(Ar⁴)d—R⁸  V2 wherein U is a unit of formula I as defined, Ar¹⁻⁴ arylene or heteroarylene that has 5 to 20 ring atoms, is mono- or polycyclic, does optionally contain fused rings, is unsubstituted or substituted by one or more identical or different groups L, provided that the Ar¹⁻⁴ groups are different from groups of the formula I, a, b, c, d are 0 or 1, and R⁷ and R⁸ are independently of each other selected from the group consisting of H, Cl, Br, I, O-tosylate, O-triflate, O-mesylate, O-nonaflate, —SiMe₃, —SiMe₂F, —SiMeF₂, —O—SO₂Z¹, —B(OZ²)₂, —CZ³═C(Z³)₂, —C≡CH, —C≡CSi(Z¹)₃, —ZnX⁰, Mg—X⁰ and —Sn(Z⁴)₃, wherein X⁰ is halogen, Z¹⁻⁴ are selected from the group consisting of C1-10 alkyl and C6-12 aryl, each being optionally substituted, and two groups Z² may also form a cycloboronate group having 2 to 20 C atoms together with the B- and O-atoms, and wherein at least one of R⁷ and R⁸ is different from H; with each other and/or with one or more monomers of formulae MI-MIV: R⁷—Ar¹—R⁸  MI R⁷—Ar²—R⁸  MII R⁷—Ar^(a)—R⁸  MIII R⁷—Ar⁴—R⁸  MIV in an aryl-aryl coupling reaction. 